The federal parliament shouldn't look to block the proposal to build stage two of the Canberra light rail, Liberal senator Zed Seselja says.
However, the incumbent senator said it was "frustrating" that large amounts of capital spending had gone towards the transport project when ACT rates were on the rise.
Speaking on ABC radio, Senator Seselja said he would wait for details surrounding the proposal to extend the light rail over Lake Burley Griffin before committing to funding for the project.
"It will be a question for the ACT assembly to see if they can afford stage two and if it's feasible," Senator Seselja said.
"I have an open mind about it, but one thing that's frustrating is so much capital spending has been spent on the light rail when rates have been going up.
"We've been seeing money taken out of capital expenditure like health to pay for the light rail."
The Commonwealth has backed the second stage of the light rail to run through State Circle on the way to Woden, rather than going through the Parliamentary Triangle.
Federal Labor has committed $200 million to construction of stage two.
Former ACT Labor senator and candidate at the upcoming federal election Katy Gallagher did not say when the funding from the federal opposition would be made available.
"That will be determined in consultation with the ACT government as stage two becomes more finalised in its design and scope," Ms Gallagher said.
"We've been frustrated because of the amount of time the Commonwealth government is having to look at these studies and committee reports.
"It's a worthy project for the nation's capital and ACT Labor will work the federal Labor to work on stage two, which people on the southside are keen to have."
The first stage of the light rail from Gungahlin to the city will open to the public on Saturday after more than two years of construction work.
While Senator Seselja said Canberrans had supported the first stage of the light rail, a determination has yet to be made about support for stage two.
"From a Commonwealth point of view, there's a national interest to make sure [stage two] fits in with the workings of Parliament House, and then it's up to the transport planners to get it right and look at what's cost effective," Senator Seselja said.
"It's a lot of money to spend and you suspect that stage two will be significantly more expensive than stage one."