"As I have made clear in the past, including when I twice appeared before the legislative committee considering this matter, at no time was I made aware of nor did I direct the deletion of emails or documents," McGuinty said in a written statement.
"In my office, it was my honour to serve alongside a hard-working and dedicated staff who, from top to bottom, were committed to the highest standards of public service"
The allegations against his former chief of staff, David Livingston, are part of an "ongoing process," he noted.
"I encourage all of us to respect this process by allowing it to come to a conclusion before we, ourselves, jump to any," he added.
His comments come after unsealed court documents alleged Livingston may have committed a breach of trust.
Provincial police say in the documents that they believe Livingston gave an outside tech expert — the boyfriend of a senior staffer — access to 24 computers in the premier's office.
It's alleged Livingston sought permission to "wipe clean the hard drives" during the transition period from McGuinty to current Premier Kathleen Wynne.
Wynne says Livingston has never been a member of her government or worked in her office.
None of the allegations have been proven in court and a lawyer for Livingston says his client has not broken the law.
Ontario Provincial Police provided the information to a court to obtain a search warrant, which they used to seize hard drives from government computers at ReCall, a data storage facility in Mississauga, Ont.
It's part of their probe into the unlawful deletion of government emails concerning unpopular gas plants in Oakville and Mississauga that were cancelled by the Liberals ahead of the 2011 election.
The police launched their investigation last June after the Tories complained that gas plant emails were intentionally deleted by McGuinty's senior staff. Privacy Commissioner Ann Cavoukian had ruled that top Liberals in McGuinty's office broke the law when they deleted the emails.
The opposition parties said the emails were wiped out to cover up the true cost of killing the gas plants, which the auditor general estimates could climb to $1.1 billion — far more than the $230 million the government claimed.
Wynne has denied accusations from the Progressive Conservatives that she possibly ordered the destruction of documents, since the special access code was still valid when she was sworn in on Feb. 11, 2013.
Wynne says Livingston and other McGuinty staffers never worked for her or her government, and they didn't have access to the premier's office since the day she took over.
But the new allegations may influence whether Ontario will be plunged into a spring election.
The minority Liberal government will fall if it cannot win the support of one of the opposition parties for its budget, whose date has yet to be announced.
NDP Leader Andrea Horwath renewed her call for a public inquiry and said a special prosecutor from outside Ontario must be appointed to work with the provincial police in their investigation.
But she won't say if the latest allegations are enough to finally pull the plug on a government her party has heavily criticized but has propped up for the past two years.
The Tories have also asked for an inquiry, but say the latest allegations are so serious that voters must go to the polls.
Horwath needs to put the public's interest ahead of her political career, said Conservative critic Lisa MacLeod.
"They have been defrauded of $1 billion, effectively, and there are criminal allegations by the OPP reaching into the premier's office, which is unprecedented," she said.
"If that's not enough for Andrea Horwath to lose confidence in a government, then Andrea Horwath perhaps should consider a different line of work."
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