Even after four weeks of campaigning, the key issue differentiating the parties remains the construction of light rail. Labor and the Greens will forge ahead with the construction of the first stage of the light rail network, the route from Gungahlin to Civic, and would sign a contract for the second, from the city to Woden, in the next term.

The arguments for light rail are numerous and go beyond the project as simply a transport option. Proponents say it is a transformative, city-building project, which will relieve congestion, integrate with plans for more buses and cycle infrastructure, drive up property prices and boost investment along the corridor, as well as providing a reliable, comfortable and efficient transport model.

The Liberals would stop construction, terminate the contract with the private consortium, and would instead redirect their attention to more buses and better roads. They say the project is too expensive, and is a poor, slow mode of transport, which will be made obsolete by technological advances like automated cars. Light rail is said not to be suited to the spread-out city, and the Liberals say large parts of Canberra would not see its benefits for many years.

Cost is a crucial issue. Stage one is estimated to cost the taxpayers $939 million in 2016, including the construction, operation, and financing costs associated with the Gungahlin to Civic route. Labor says the second stage to Woden will cost a similar amount. Crossing the lake, however, is likely to drive up the price. Labor says the amount is a fraction of total expenditure on other services such as health and education, and must be considered over a 20-year time frame, which will largely spread out any burden on taxpayers. They also point to a Treasury figure that estimates cancelling the contract would cost up to $280 million, but achieve nothing.

The Liberals say the project is unaffordable, and say the government will need to increase rates or add new taxes to fund it. They have used an estimate of the entire light rail network, including all stages, produced by former Treasury official Khalid Ahmed. Ahmed said the whole-of-life expenditure for the entire five-stage network would be roughly $14 billion, in nominal terms.

Both parties have also announced major investments in buses, including in the Rapid network.

The traditional battleground of health was an early focus for both main parties. The Liberals drew first blood, promising a new $395 million Canberra Hospital building, including a new operating suite, medical imaging suite, intensive care unit and outpatient floor. They based their model on a Labor plan, which was shelved in 2013.

Labor responded by pledging to spend $570 million on a new building at the Canberra Hospital, a new emergency department and an expansion to the recently completed women and children's hospital on the same campus. The Liberals want to build small satellite hospitals in Gungahlin and Tuggeranong, describing them as "emergency departments", a term that has drawn concern from some doctors and paramedics. Labor says it would build two new nurse walk-in centres in Weston Creek and Gungahlin.

Both parties have made smaller pledges to encourage bulk-billing GPs, recruit more nurses, and boost the indigenous health service Winnunga Nimmityjah. Labor has also announced a nurse training package and preventative health measures.

The centrepiece of the government's tax-reform agenda is the abolition of inefficient taxes such as stamp duty, and replacing them with higher rates. It's a 20-year plan that began five years ago. The reform is politically challenging, and has meant about 10 per cent annual rises in rates year on year for four years.

Rate rises were slowed in this year's budget, when the increase to rates was halved to about 4 per cent. But rate rises will go back up to roughly 7 per cent annually after the election.

The Liberals have made hay of the rate rises, using it as the central plank of their attack on Labor again in the 2016 election campaign. The Liberals are promising "lower rates" in their political advertising, but are yet to spell out their own tax plan. They are expected to do so before the election on Saturday.

Education has not proven to be the intense battleground of prior campaigns, although there have been significant commitments from both sides. The Liberals have promised land for a new Catholic school in Molonglo, and land for a new private school in West Belconnen, an $100 million package for special needs support and upgrading government and independent schools, and flashing lights in school zones.

Labor wants to give every high school and college student an iPad, and would spend about $100 million on capital upgrades for public and independent schools. It has also pledged a scholarship scheme to give 25 teachers postgraduate qualifications in science, technology, engineering, maths or languages.

Concerns about questionable land deals, such as the Glebe Park purchase, and the closeness of links between the government and developers have driven pressure for all parties to act on government integrity. Initially, only the Greens were willing to commit to creating an ACT independent commission against corruption. The Liberals, who had savaged Labor over the "smell" around the government, originally baulked at an ICAC, but later promised they would set one up, if elected. The Liberals would also double the workload of the Auditor-General, and establish an independent public service commissioner.

Labor has promised an ACT integrity commissioner, which would have the power to conduct hearings and recommend criminal prosecution. Labor would ban donations from property developers, introduce real-time reporting rules, expand the lobbyist register, and investigate the public funding of election campaigns.

For the first time, Canberrans will be voting for candidates across five electorates, to elect 25 members to the Legislative Assembly. Three electorates are considered crucial for the major parties: Yerrabi, covering Gungahlin, Ginninderra, mostly the Belconnen area, and Murrumbidgee, which is Woden and Weston Creek. The Liberals face a real challenge. They will need to win a majority, or 13 seats, in their own right, given the Greens have repeatedly said they will not form government with them.

Labor and the Liberals are highly likely to get two spots in each of the five electorates. That means the election will be decided on who wins the remaining fifth seat in each electorate. The Liberals will need three of the five to win a majority and form government. Their best chance to pick up a third seat is in Brindabella, but the other two will be harder to come by. Ginninderra is traditionally a stronger Labor vote, and could potentially give them a third seat, while few are willing to pick Yerrabi and Murrumbidgee.

The Greens are expected to at least retain their seat in Kurrajong, the central Canberra electorate, boosting Labor's prospects. The Liberals, on the other hand, will be hoping that conservative independents or members of the minor parties break the usual dominance of the three main parties and win a seat, something that remains an unlikely prospect. The Hare-Clark system will require a candidate to win a quota of 16.7 per cent, a significant barrier for minor parties and independents.

All of these predictions are precarious, given the number of unknowns in this election, a situation not helped by the lack of any publicly available polling.

Christopher Knaus is an ACT political reporter.