TORONTO -- The Ontario government's top IT official testified Tuesday that he had been directed by cabinet office to give special computer administrative rights to a top aide to former premier Dalton McGuinty.

Chief information officer David Nicholl told the legislature's justice committee that he didn't have the authority to give McGuinty's chief of staff, David Livingston, the special access to computers in the premier's office.

"I was directed by cabinet office to proceed with implementing the admin rights for premier's office computers, and to expect a call from the premier's chief of staff," said Nicholl. "Typically, the control for all of the PCs in the premier's office, that's why I don't have the authority to touch them, would always go through the CAO within cabinet office."

Cabinet office supports the work of the premier and the cabinet and has government-wide responsibilities.

The OPP is investigating possible breach of trust charges for the alleged deletion of correspondence on the Liberals' decisions to cancel two gas plants prior to the 2011 election, at a cost of $1.1 billion.

In his third appearance at the committee hearings into cancelled gas plants in Oakville and Mississauga, Nicholl said Livingston had told him he wanted the computer hard drives wiped before Kathleen Wynne took over as premier on Feb. 11, 2013.

"He first requested information about decommissioning email accounts for departing members of the premier's staff," said Nicholl. "He then asked for administration rights to PCs used by staff in the premier's office to enable the cleanup of hard drives prior to the new team coming in."

Livingston had been warned that it would be inappropriate to delete email accounts when they could contain gas plant documents requested by a legislative committee, he added.

"I received a couple of emails from cabinet office legal counsel with the legal memo that I (was) to both read out to the chief of staff (Livingston) and then to actually send to the chief of staff," Nicholl testified.

Nicholl also said he did not know Laura Miller, Livingston's deputy chief of staff, or her boyfriend, Peter Faist, the outside IT expert that the OPP say was brought in by Livingston and given the all-access administrator's rights to computers in the premier's office.

Police seized 24 hard drives that had been removed from computers in the premier's office but so far experts have only been able to retrieve data from four of them. All four were accessed with the special administrator's password on Feb. 6 and 7, before Wynne was sworn in. The administrator's password was valid until March 20, 2013, but the computer techs can't say yet if it was used after Feb. 7.

Nicholl also denied having a long-standing friendship with Livingston, saying the two had attended some of the same meetings when they both worked for TD Bank 22 years ago but hadn't remained in touch or ever been friends.

The New Democrats said Livingston wanted the hard drives in the premier's office wiped clean and knew the unusual request would be considered because he was McGuinty's top aide.

"Mr. Livingston took actions, political in nature, that were very outside of the normal actions that one should be taking," said NDP critic Jagmeet Singh. "It was very clear that Mr. Livingston wanted that password and went to whatever steps necessary to get that, and he was very persistent."

The Progressive Conservatives complained about inconsistencies in Nicholl's testimony about the granting of the administrator's access to computers and his statement to OPP investigators, and cautioned Nicholl against perjury in his testimony.

"He's entitled to his own account, but it is inconsistent with what we've been told by the OPP," said PC energy critic Lisa MacLeod.

The veteran civil servant insisted he was telling the truth, but admitted he was unprepared for his police interview and had made mistakes.

"Please do not assume. I am not perjuring myself here in any way, Ms. MacLeod, not at all," said Nicholl.

It was a contempt of parliament motion based on the Liberals' initial refusal to turn over all the gas plant documents that prompted McGuinty to resign in Oct. 2012 and prorogue the legislature for four months until Wynne was picked as the new party leader and premier.

Ontario's Information and Privacy Commissioner also lashed out at the governing Liberals for what she said was the illegal deletion of gas plant emails in a special report last summer.