Derryn Hinch has stared down fierce criticism for striking a deal to delay the implementation of the Turnbull government's building industry reforms.

Construction companies will be given two years to become compliant with the workplace changes, with EBAs to be protected until November 2018, despite a new building code tied to Australian Building and Construction Commission laws which passed parliament on Wednesday.

"It must be a good outcome because the unions don't like me over it, the major builders don't like me over it and I'm very happy, and the government's signed off on it," Senator Hinch told The Australian.

The CFMEU says it's nonsense for the government to claim the cost of building and the price of new homes will be cheaper under the ABCC laws.

"In six months, or 12 months, time the Australian people will be able to examine those propositions that have been put forward by the government and they will be seen to be false and hollow," construction arm national secretary Dave Noonan told ABC radio.

Prime Minister Malcolm Turnbull said the two-year transition period applied only to enterprise agreements struck before the ABCC laws become operative.

"It means that those companies over the next two years are still able to tender for government work even though their enterprise agreement is not compliant," he told ABC's 7.30 program.

"But they will have to start bringing their arrangements into line with the code from day one."