The release of population data the the 2016 census results this week made a third Canberra electorate in time for the next federal election likely, as the Parliamentary Library forecast the House of Representatives growing to 151 members.

Changes in the required quotas are expected to see Victoria gain a new seat, with South Australia losing one.

Data prepared by the ACT government suggests the territory will overtake Tasmania's population sometime between 2029 and 2035, with Canberra's current 11.2 per cent growth rate suggesting there will be more than 200,000 new residents within 20 years. Tasmania would have to main its 2.9 per cent growth.

ACT growth of around 12.5 per cent, combined with a slightly slower growth in Tasmania could see the ACT move ahead as soon as 2029.

As one of the original states at Federation, the Constitution guarantees Tasmania five lower house seats.

Electoral analyst Ben Raue said he expected a Tuggeranong-based seat, a central seat and a Belconnen and Gungahlin seat would be created by the likely redistribution.

"Essentially both the existing seats will change dramatically. A northern seat which loses the inner north of the city becomes quite a different seat.

"When you take two and turn them into three, you are effectively creating three new electorates," he said.

The author of the Tally Room blog, Mr Raue said the new seat could withstand future redistributions.

"The ACT is growing quite fast now but the proportion of the state you need to get a bigger seat is much larger there. The territory will have to keep growing faster than the rest of the country to maintain three seats," he said.

Predictions of the territory easily passing the required 2.5 population quotas needed for the new seat from analysts, academics and political wonks has the major parties sizing up their options. Some share the expectation Labor would hold a new electorate outside of any future Coalition election landslide win.

Acting ACT Chief Minister Yvette Berry said new electorates needed to keep up with Canberra's quick growth.

"People are moving here faster than ever before for our high standard of living and high quality jobs, healthcare and education services," she said.

"The ACT is on its way to becoming the sixth largest jurisdiction so investing in better infrastructure, roads and public transport to support our population is important to our community."

Canberra MP Gai Brodtmann represents the most populous electorate in Australia, ahead of Fenner MP Andrew Leigh. On Wednesday, Dr Leigh said a third MP would improve representation for constituents.

"It certainly means that you have a fuller inbox," he told the ABC.

"Your phones are ringing off the hook and people are coming in the door more often than they would be in smaller electorates.

"I speak a lot with my parliamentary colleagues about the work we all do representing electorates and yes, there's challenges across the board. People in far north Queensland are representing huge electorates, but the sheer population in the Canberra electorates does place strains on."

ACT Greens convenor Michael Mazengarb said the party could win a central Canberra seat.

"While each of the current federal seats in the ACT have remained safe Labor seats for over two decades, Canberra residents receive little attention when it comes to election commitments from either the Labor or Liberal parties.

"The ACT Greens see the establishment of a third ACT federal seat, particularly one based around central Canberra, as one that could be quite winnable. A genuine contest for federal seats in the ACT would only be to the benefit of the Canberra community."

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