Some already owed large sums of money from the financially troubled Nishi apartments project at Acton have been waiting five months for payment.

They have also been sued by the ACT government for ''liquidated damages'' - including claims of $15,000 a day for being late completing work.

At least three subcontractors have engaged barristers and say the government is breaking its own laws by not paying them on time.

Shared Services Procurement referred questions from The Canberra Times on Wednesday afternoon to a spokeswoman for ACT Health. She said on Thursday the project was on budget and on time.

The spokeswoman said she was still waiting on responses to questions from senior executives.

On Friday morning, she confirmed that payments had been made.

Construction of the Capital Region Cancer Centre began in November with fanfare from then federal Health Minister Nicola Roxon, ACT senator Kate Lundy, who features in a YouTube video for the sod turning, and Chief Minister Katy Gallagher.

The five-storey centre, due for completion this year, will integrate chemotherapy, radiation therapy, haematology, immunology and research and teaching programs.

But contractors said the project, to be delivered by Shared Services Procurement and consultant IQON Construction Management, was behind almost from the start.

Facade consultant Gene Levette told ABC Radio that if any payments had been made to subcontractors, they came very late on Thursday evening or early Friday morning.

“It looks like money has been paid for one subcontractor, but the Façade company is owed in the order of about $800,000,” he said.

Mr Levette, who managed design, engineering, workshop drawings and procurement, said contracts were awarded too late.

''This job is something completely out of the ordinary, '' he said.

Mr Levette said the site was not ready for him to begin work on March 4 but he was slapped with liquidated damages of $15,000 a day from that date.

About three weeks ago he attended a site meeting to sort out disputed claims with the government's representatives only to be stood up. Another meeting was scheduled. ''We go there at 9am. We are driving down from Sydney, they walk in and say, 'We'll give you 15 minutes, that's all we've got,''' he said. ''We just want to tell you face to face, we are not going to pay you. 'You owe us more than we owe you.'''

So far Mr Levette has spent $80,000 on legal fees trying to recover money.

''Everyone is under the same hammer. I think our figures are $750,000, airconditioner [subcontractor] is $500,000, the plumber is $300,000,'' he said.

Construction, Forestry, Mining and Energy Union secretary Dean Hall said disputes arose from excavation through to plastering, when electrical work was not installed beforehand in wall cavities.

''There's always disputes between subbies and the builder,'' he said. ''This one has more than average.''

Instead of receiving a progress payment of $800,000, a subcontractor providing windows, curtain wall and aluminium doors, has received a liquidated damages claim for $1.15 million.

He was forced to pay $60,000 for storage of windows and cannot get reimbursement.

''They can't justify what they're doing,'' the man said. ''I have to look after my family.

''What they have done is starved me of money. They haven't paid for variations.

''We were told not to install windows until February 28. Then they gave an extension of time till March 4 to install five levels of windows.

''It's an absolute disgrace. I have a solicitor, litigation lawyer and barrister [at $16,000 a day].''

Another subcontractor said recovering lost time caused by incorrect scheduling or late finishing stages quickly racked up compression costs - hiring extra people to finish a job in half the allotted time.

Subcontractors are frustrated and furious Shared Services Procurement and IQON have allegedly dodged meetings and refused to agree to extensions or negotiate variations to work. They say specifications were changed, re-engineering and redesign were ordered, yet those overseeing the work refuse to pay for the extras and the government has ignored legal claims for the money owed.