Before the government gives final approval in October on building the line linking the city to Gungahlin, Ms Gallagher said there would be detailed study and planning for the relocation of power, water and telecommunications infrastructure.

The comments came after Fairfax Media reported concerns about the pipes and wires under the route of Sydney's proposed $1.6 billion light rail line had prompted one of the leading international bidders to withdraw.

Balfour Beatty, the largest construction company in Britain, reportedly withdrew from the project citing fears of cost overruns in relocating utilities under Sydney's George Street, one of the city's oldest and busiest roadways.

A company spokesman said the decision had been based on ''commercial reasons.

Just two groups are expected to bid for the right to build and operate Sydney's tram line, amid concerns that state authorities may be underestimating the difficulty of building tracks in the central business district.

Sydney's light rail line is set to serve the city and eastern suburbs.

Last week Capital Metro Minister Simon Corbell announced the start of a four-month, $1.3 million study along Northbourne Avenue, the Federal Highway and Flemington Road, which will see more than 1000 holes dug to establish the location of pipes and wires.

Ms Gallagher dismissed the concerns and said there was strong Australian and overseas interest in the construction and operation of Canberra's light rail.

She said industry interest would be tested in coming months.

"We know that there are a lot of utilities under Northbourne Avenue and when you look at light rail projects, particularly the ones in Sydney and even the Gold Coast … we have a relatively easy path in terms of where we want to build this,'' Ms Gallagher said.

"But Northbourne Avenue presents us with some challenges. That's why all the detailed work that is being done now by Capital Metro is so important to inform the government of future decisions and once those decisions are taken, how we package that work out to the private sector, if that’s ultimately where it goes.''

The government is yet to announce if the cost of moving pipes and wires would be separate to the overall $614 million budget.

"I am very confident that we have a good and thorough understanding of all the complexities of the project, including everything that is travelling under Northbourne Avenue and where that should go, before we take those decisions, so that problems like what we are seeing in Sydney don't happen," Ms Gallagher said.

"I have to say that I am knocking back meetings with people who are interested around light rail because I think we need to get some of our thinking in place first, but there is a lot of interest."

Speaking after opening a forum with business and community leaders on the light rail project, Ms Gallagher said she was regularly briefed by Capital Metro director Emma Thomas.