Hundreds of people will get a chance to ride the light rail on Thursday, ahead of its official opening on Saturday.

But on Wednesday, Transport Canberra and Canberra Metro were still waiting for regulators to officially sign off on the project.

The project required three key accreditations - from the technical regulator, the National Rail Safety regulator and the independent certifier.

It is understood the community loop would have proceeded whether or not accreditation came through.

Officials had hard hats and high-vis vests on hand for members of the public on the off-chance it did not.

However Transport Minister Meegan Fitzharris' office confirmed accreditation came through late on Wednesday afternoon.

Earlier in the day, Ms Fitzharris told The Canberra Times she was confident the project would be signed off on before Thursday.

"We're literally waiting for some documentation to exchange hands but clearly the system is safe now, it's close to full operations over the last few days particularly so there's never been a concern about the safety of the system testing, it's just that final piece of the puzzle," she said.

Ms Fitzharris said the final accreditation of the project was "always going to come quite late in the piece".

"It's just the nature of these big projects," she said.

Transport Canberra deputy director-general Duncan Edghill also confirmed accreditation was on track.

"It was always anticipated that the independent certifier would happen right at the last second, because, by definition, as soon as you've got that you're into operations the next day," he said.

Project director Meghan Oldfield said it was common for accreditation to come through this close to operations beginning.

"I've never been on a project where I've had the luxury of time," she said.

Even after services commence on Saturday, construction and landscaping will still occur along the alignment, she said.

"There will still be works, which we'll call remaining works, which will be noticeable to the public and that will happen after [Saturday], there might be some landscaping or some completion of asphalting and some of those kinds of things will remain after, but the goal will be to have anything safety related or impacting passenger services to have that complete before we start operations," Ms Oldfield said.

Mr Edghill said none of the remaining works would have anything to do with customer safety or the operating system.

"It's really about putting that final polish on the system," Mr Edghill said.

Tens of thousands of people are expected to attend the light rail launch on Saturday, with free rides and entertainment at the Civic and Gungahlin stations.