Catholic Schools NSW boss Dallas McInerney has been accused of destroying evidence that could be relevant to a corruption inquiry following testimony which could put him out of a job and, if proven he deleted the information to prevent its use in the inquiry, expose him to potential criminal charges.

The senior counsel leading the Independent Commission Against Corruption’s case against a group of conservative Liberal Party operatives was left dumbstruck when McInerney revealed he had performed a factory reset on his iPhone and iPad over the weekend while still sworn in as a witness.

McInerney’s shock evidence on Wednesday wrapped up the first phase of Operation Rosny, which is investigating allegations of illegal political donations and government corruption. The commission will on Thursday turn to damaging claims fugitive Sydney developer Jean Nassif paid a $2 million bribe to three Liberal Party figures.

McInerney claimed he erased everything on his phone because the National Australia Bank had placed a block on his main spending account due to a suspicious overseas transaction. But he was not advised to wipe his phone by the bank, and he did not tell his high-powered legal team he was going to do it.

He acknowledged knowing that a factory reset would erase all content and settings on his device.

“It’ll be a matter for the commissioner, but can I suggest that is a transparent attempt by you to wipe evidence that would have been critical for this commission?” counsel assisting the ICAC, Dr Peggy Dwyer, SC, said to McInerney.

McInerney also performed a factory reset on his iPad. Asked why, he said because he had voluntarily decided to hand it and his phone back to Catholic Schools NSW even though the organisation hadn’t asked for them. He later said his Apple Pay function was also on the iPad.

McInerney, who has led Catholic Schools NSW for almost a decade alongside his role as a Liberal Party powerbroker, said he had decided to return the work devices to Catholic Schools NSW given “I’m not likely returning to the company”.

“You can put whatever complexion on it you like, but I think my track record of cooperation in this inquiry speaks for itself,” McInerney said.

Any person who knows that a document or other item may be required for an ICAC investigation and wilfully destroys it to prevent it from being used in an inquiry is guilty of an indictable offence, which can include prison time of up to five years. McInerney has not been accused of such conduct.

McInerney stepped aside from his role at Catholic Schools NSW last month but remained on the books. The organisation did not respond to a series of questions from the Herald on Wednesday, including whether McInerney was still employed and whether the organisation stood by him.

The ICAC alleges McInerney potentially broke donation laws by directing hundreds of thousands of dollars towards a conservative Christian Liberal Party sub-faction known as the Reformers.

Investigators claim up to $265,000 in schools funding was diverted to two companies, Beckington and JPG Advisory, via sham invoices. Beckington was run by Christian Ellis, a key figure behind the Reformers, as well as lobbyist and former political staffer Jeremy Greenwood.

Only hours before deleting his iPhone and iPad, McInerney had been ordered by the ICAC to produce a series of messages between himself, Ellis and Greenwood.

After winding up his second day of evidence last Friday at 1pm, McInerney said he went to the Hunters Hill Hotel with his sister and niece and was unable to pay for several items, due to an issue with his account. He said after visiting the pub, he complied with the ICAC’s order to produce certain messages with Ellis and Greenwood from a defined time period.

He contacted his bank on Saturday about the account issue and later performed a factory reset on his phone and tablet – actions he said were motivated by a concern a fraudulent actor could gain access to his Apple Pay function.

“My track record has been full co-operation with this commission,” McInerney said. “If you’re talking some malfeasance on the factory reset, I’ve been on notice for two months about this inquiry. I could have taken that step at any time.”

Dwyer replied: “You’ve been on notice about this inquiry, but it wasn’t until Friday that anybody called for your messages. And it’s just a coincidence that after the calling of your messages, the very next day you performed a factory reset on your phone. You can see the basis for suspicion, can’t you?”

She said McInerney’s decision to wipe his phone meant the ICAC would struggle to request other material it may need in the future. She also said McInerney hadn’t mentioned anything about wiping the devices when the topic of his communication came up earlier on Wednesday morning.

Dwyer said it was “just too cute” for McInerney to suggest he had been genuinely forthcoming to the commission.

The ICAC claims funding for the Reformers between 2019 and 2023 ultimately benefited the Liberal Party and therefore constitutes a political donation. McInerney has repeatedly denied knowledge of such a scheme.

Dwyer spent much of Wednesday putting to McInerney a deluge of communications between himself, Ellis and Greenwood over several years. She said the large volume of messages about Liberal Party matters, but an absence of communication involving any actual work for Catholic Schools NSW, was proof the contract was a sham.

One message from McInerney included his description of federal Liberal MP Melissa McIntosh as “dumb as dog shit”. He also said the MP for the western Sydney seat of Lindsay had the “penmanship of a junior high schooler”.

The commission will on Thursday move to evidence from former fair trading minister Eleni Petinos and her former chief of staff Cassandra Lawry.