Cases will officially be heard in new courtrooms from Monday, with stage one of the $160 million Canberra court revamp completed.

Media were given a sneak peak on Thursday of the new facilities, which includes six courtrooms, chambers, a library, public entry, jury facilities, and a dedicated remote witness zone with seven video conference suites and waiting areas.

The project has been beset by delays, with stage one initially scheduled to be completed late last year, after expansion works started in March 2016.

However, as the project has been undertaken via a public-private partnership, the delay will come at no extra cost to the ACT Government, Attorney-General Gordon Ramsay said.

Chief Justice Helen Murrell admitted the construction phase had been "a great juggling act", but the wait had been worthwhile.

"It's fantastic, it's really appropriate for Canberra and it says great things about the Supreme Court and where we’re headed," the judge said.

"We've got all the facilities we need, for now and into the future so we're absolutely delighted.

"We’ve been operating in caves with no light."

Chief Justice Murrell expected the new facilities would improve court productivity and wait times for defendants.

Mr Ramsay said the completion of stage one had brought the capital's justice system into the 21st century.

"We think the facilities we have here are really world class and [we're] very pleased to have our judicial officers, our legal fraternity … and the public being rewarded with a facility that Canberra deserves," he said.

Mr Ramsay said the new facilities would deliver a more timely, transparent, and accessible justice system.

"Which is especially important as Canberra's population continues to grow," he said.

The current ACT Supreme Court building is 55 years old, constructed in 1963 to service a population of 100,000.

The ACT's population has since boomed to about 400,000.

Mr Ramsay said cutting edge technology was a major feature of the new court facilities, with all courts equipped with state of the art systems that allow multimedia evidence to be broadcast to all participants and the public gallery simultaneously.

"We are now able to ensure that everyone involved in a particular case is quite literally on the same page," he said.

Mr Ramsay said stage two of the project – the refurbishment of the existing heritage Supreme Court building – could now get underway.

Phase two will include the construction of two court rooms, mediation suites, hearing rooms and spaces for justice support groups.

He expected the works to be competed by mid-next year.

Other works to be completed on the complex includes the completion of the new public lobby, the installation of feature artwork, work on the facade, and landscaping.