A Transport Canberra spokeswoman said the problems were caused by changing weather conditions and would have no impact on the cost of the project borne by the territory.

"Changing weather conditions during a concrete pour can affect the end quality of the concrete. In instances where installed concrete does not meet quality requirements in accordance with the project’s specifications, it may be required to be removed and reinstalled. This is a cost borne by Canberra Metro," she said.

"Steel contracts and expands with changes in temperature. As the rail is not fixed solid as heavy gauge, some movement may occur."

It's understood the problems meant the rails were not parallel in some parts.

The spokeswoman said rectification works had occurred at "various locations" along the Gungahlin to city corridor, including on Flemington Road and at the entrance to the light rail depot.

"Re-work is an unfortunate but expected element of large, complex infrastructure projects. This is a very visible project stretching for 12 kilometres, so members of the public can see what is happening on the site more easily than on other work sites around Canberra," she said.

Asked whether all the areas had been fixed, the spokeswoman said: "Construction is ongoing and there are independent certifications which will need to be obtained by Canberra Metro. Until all construction, testing and commissioning is complete, it is always possible that some areas may need further work."

The spokeswoman said the concreting was not one of the variations still being negotiated with the consortium.

"Under the contract, Canberra Metro is obliged to ensure work is of a satisfactory quality," she said.

Earlier this week, Under Treasurer David Nicol told annual reports hearings talks were under way about a number of unresolved contract variations.

Variations that have been approved over the last two years have largely cancelled each other out, with the territory yet to pay any of the $117 million contingency to Canberra Metro and the project still expected to be delivered in budget.

The consortium recently pushed back the operational commencement date of light rail from December 21 this year to January 2019, although that date could be subject to change again.

The delays were attributed to the complexity of the project, safety and the need to obtain third party accreditation from the Office of National Rail Safety Regulator and the independent certifier before passenger services start running.

Earlier this week, a spokeswoman for Transport Minister Meegan Fitzharris said the government would continue to provide information about the project "as appropriate, including updates to the expected opening date as that point draws nearer".

"The ACT government has been very transparent with the project to date, having published its business case, the contract and the future availability payments," she said.

Meanwhile the construction disruption continues along the southern end of the light rail route, with a total closure of Northbourne Avenue northbound between the Mouat-Antill Streets intersection and the Barton Highway this Friday and Saturday nights, from 8pm to 6am.

There will be detours in place to reach the Netball ACT precinct and the Yowani Country Club.

There'll also be night-work from Friday to Monday with road asphalt taking place on the northbound lanes of Northbourne Avenue at the Swinden Street intersection.

For a full list of road closures, head to the Canberra Metro website.