TORONTO -- Premier Kathleen Wynne is facing calls by the opposition to step down after police laid criminal charges against a Liberal fundraiser in connection with a byelection in Sudbury, Ont.

Gerry Lougheed, a prominent Sudbury Liberal, was charged Thursday with one count of counselling an offence not committed and one count of unlawfully influencing or negotiating appointments.

The charges follow a Ontario Provincial Police investigation launched after Andrew Olivier, the Liberal candidate in the 2014 general election, said he was offered an appointment to step aside in the Feb. 5 byelection for Wynne's preferred candidate, former New Democrat MP Glenn Thibeault.

Olivier released recorded telephone conversations with Lougheed, whom he describes as "a Liberal king maker" and with Wynne's deputy chief of staff, Pat Sorbara, in which he said he was asked if he wanted a job or an appointment.

The charges were announced just minutes before the daily question period in the Ontario legislature.

"This case strikes right at the heart of the premier's office," said Progressive Conservative critic Jeff Yurek. "Will the premier step aside while these charges are before the courts?"

Deputy Premier Deb Matthews ignored Yurek's demand, but told the legislature that the OPP had advised Sorbara's lawyer that she will not face charges in connection with the byelection.

"This matter is before the courts and we ill have no further comment," Matthews said. "We co-operated fully with the police and we trust the court system to do its work in a fully independent way."

NDP house leader Gilles Bisson said Wynne had defended Lougheed's actions and he wanted to know who was behind the offers to Olivier.

"Who ordered Lougheed to break the law on behalf of the Liberal party," asked Bisson. "What did the premier know and when did she know it?"

Wynne always maintained the Liberals were just trying to keep Olivier in the party fold, and that there was no need to offer him a job or appointment to step aside because she had already decided he was not going to be the candidate in the byelection.

OPP investigators questioned Wynne in April about Olivier's allegations against Lougheed and Sorbara, but despite opposition demands the premier never removed Sorbara from her office.

The Progressive Conservatives and New Democrats called it appalling to see a sitting Ontario premier being questioned by police.

Both Sorbara and Lougheed have denied the allegations.

Elections Ontario concluded months ago that Lougheed and Sorbara's actions constituted an "apparent contravention"' of the Election Act concerning bribery, but the agency has no mandate to conduct prosecutions.

Thibeault won the byelection for the Liberals, taking back the Sudbury riding that they had lost to the New Democrats less than a year earlier.