Outgoing Ontario Premier Dalton McGuinty has downplayed the effects of his decision to prorogue the provincial legislature, saying the government will sit for just 18 fewer days as a result of his decision.

In his first news conference since stepping down, McGuinty said Wednesday he shut down government because "things were becoming overheated" in the legislature. He rebuffed opposition claims that the move came as the result of his party needing to rebuild, or to avoid contempt motions related to the contentious cancellation of two power plants.

"I appreciate the varying perspectives out there, but there is only one person who has been assigned the responsibility of ensuring the legislature functions at all times in the public interest. And my conclusion, my judgement was we were no longer fulfilling that responsibility," McGuinty said. "Things were becoming overheated and the legislative process was in danger of seizing up entirely."

The premier also noted Ontario's legislature sits longer than any other province, and MPPs started summer break two weeks late and returned two weeks earlier than normal this year.

"The combined effect of those extra days, plus prorogation, means we are going to lose 18 legislative days. Just to put that into some perspective," he said.

McGuinty blamed the opposition for the heated climate in the legislature, saying they have asked for debate adjournment on 45 occasions, "consumed an entire week with a spurious, phoney contempt motion," and outright rejected the Liberals' public sector wage-freeze proposal when an advance copy was sent to leaders as a "courtesy."

"I blew a whistle and said alright, everyone out of the pool. Let's let the waters calm and let's use our time productively," McGuinty said, adding that efforts to resolve the public-sector dispute are ongoing in spite of prorogation.

At one point, a reporter pointed out that the opposition parties had not "rung the bells" – a term for requesting an adjournment of debate – since the spring, suggesting McGuinty's real motivation was to avoid contempt motions that were "piling up" over the controversial cancellation of the two gas-fired power plants.

McGuinty outright rejected that suggestion, saying the decision was practical, not political.

When asked when the prorogation would end and MPPs would return to work, McGuinty said that decision would be up to his successor.

In the days leading up to McGuinty's decision to step down, the opposition accused senior cabinet ministers of misleading the legislature over documents related to the cancelled power plants, and the Progressive Conservatives asked Speaker Dave Levac to rule if there is evidence some members deliberately misled the legislature.

Additionally, Energy Minister Chris Bentley is facing a possible contempt censure over his refusal to release documents to a legislative committee last May. Just three days before McGuinty's announcement, the government released 20,000 pages of documents that were not part of the initial disclosure.

With the prorogation now in place, all ongoing business comes to a halt, including the move to discipline Bentley.

McGuinty had surprised many in announcing his resignation – and the subsequent prorogation – on Oct. 15. He has been leader of the Ontario Liberal Party for 16 years, championing his party through three consecutive election victories.

McGuinty will stay on as leader until a successor is chosen in late January.