Safety standards on a Melbourne building site where a worker died were "extremely poor", a site construction manager has told a royal commission into trade union corruption.

Michael Bonnici said the developers of the old Pentridge Prison site also asked him to bribe a power company worker to get power hooked up early.

But counsel assisting the royal commission Jeremy Stoljar SC said Mr Bonnici was making up his allegations in order to hurt developers Peter and Leigh Chiavaroli.

Thomas Kelly died in an industrial incident in October 2009, after which the CFMEU got involved with the Pentridge Village project.

“I think that the Chiavarolis wanted me off the project because I would speak my mind, and would not bend to adopt the low standards they applied on the site,” Mr Bonnici told the commission on Thursday.

He said safety standards on site were “extremely poor” and he was told to do as little safety work as possible.

Mr Bonnici told the commission he was sacked, but Mr Stoljar said Mr Bonnici left after the Chiavarolis refused to pay him more money.

Mr Stoljar said Mr Bonnici’s bribery claim was false, but Mr Bonnici offered to provide the commission with the phone number of the contractor to check he was telling the truth.

Mr Bonnici said he had gone to the Fair Work Ombudsman and the Australian Building and Construction Commissioner, but no one had taken up his case.

He said legal disputes with the Chiavarolis and another builder had left him bankrupt, and he got no help from the CFMEU.

“I was and remain very disappointed by the failure of the CFMEU to provide me with any assistance,” Mr Bonnici said.

CFMEU official Anton Sucic told the commission he started work at the Pentridge Village site after Mr Kelly’s death to ensure it was safe.

He denied he was on site purely to sign contractors up as CFMEU members.

“We live in Australia, it’s a free country, I explained my position and I gave them the choice,” Mr Sucic said.