A legal dispute between the WA Government and builder John Holland does not look like ending soon.

The Perth Children's Hospital (PCH) opened three years late after a string of problems which have now landed the WA Government and John Holland in court, suing each other over the delayed project.

The Government wants compensation from John Holland for the delays in completing the hospital, while John Holland is seeking more than $300 million in damages for what it considers “significant changes that the state made to our scope of works on PCH”.

Reports say the Government recently offered John Holland $20 million to end the dispute.

But Treasurer Ben Wyatt has refused to comment on the deal, accusing the company of using a “clear litigation tactic” of leaking information to the media.

He says this is designed to weaken the state government’s position during negotiations.

Mr Wyatt said the dispute will probably head to court.

“It would be a travesty for me to comment in the media in response to what is a clear litigation tactic by John Holland, for selective media leaks to get me to come out and say something that might compromise the position. I'm not going to do that,” Mr Wyatt said.

“I don't want to go to court, but suffice to say I'm also simply not going to be treated like a fool by an organisation that wants me to write a big cheque.

“It's not going to happen that way. So I was hoping this would be resolved, but it appears with this latest leak from John Holland that's likely to be where we go.”

Opposition Leader Mike Nahan said the Government clearly made an offer to John Holland.

“This is an issue of accountability. The Government took possession when it shouldn't [have] and with great bravado said it was going to get money from John Holland. It's blown up in its face,” Dr Nahan said.