An Ottawa-area legislator could become the interim leader of Ontario's Liberals, who suffered their worst defeat in party history in last week's provincial election.

The Liberal caucus, which was reduced to seven members, unanimously endorsed John Fraser for the position on Wednesday evening.

Their selection will be voted on over the next 24 hours by party executive members and riding association presidents who do not have elected legislators representing them at Queen's Park, the party's president, Brian Johns, said.

Fraser, a backbencher in the Liberal government, was first elected in a byelection in 2013 that was called after former party leader Dalton McGuinty stepped down.

The statement comes on the same day that the Liberals held their final cabinet meeting with an eye to rebuilding the party that governed the province for the last 15 years.

The majority of Liberal ministers lost their seats as their Progressive Conservative rivals secured a majority, and many acknowledged their party now faces real challenges.

Emerging from the back-to-back meetings with cabinet and caucus, outgoing premier Kathleen Wynne — who resigned as Liberal leader on election night — acknowledged it was an emotional day with her defeated party members.

"That it's coming to an end, this part of it, it's a challenge," she said. "But it has been such an honour to serve and I'm going to continue to find ways to serve both my constituents and the people of the province."

Michael Coteau, the province's minister of children and youth services, who was re-elected in a hotly contested race, said the party must now figure out what went wrong (CBC) Michael Coteau, the province's minister of children and youth services, who was re-elected in a hotly contested race, said the party must now figure out what went wrong.

"[We must] better understand why that collapse took place," he said.

"Where was the disconnect between our party, our brand, and the people of Ontario? And how do we re-establish that relationship and that trust?"

Economic Development Minister Steven Del Duca, who was defeated in his suburban riding north of Toronto, said the desire for change was "visceral" while campaigning.

"I think the party needs to take a bit of a step back," he said. "Do all of the analysis that's required when you face this kind of result ... we've done this before and we've managed to rise again. And we will, but it will take time."

An emotional Kathleen Wynne acknowledged during the campaign that she will no longer be premier after the June 7 election. She resigned as party leader on election night. (CBC) Longtime Liberal legislator Michael Gravelle, one of the seven Liberals to be elected, acknowledged that the coming months will be tough.

"You could feel a difference at the doors," he said of the campaign. "It was apparent to me that we were in a very competitive race from the very beginning ... It will be a real challenge."

Compounding the issue is the fact that the Liberals are now one seat short of qualifying for official party status, which means they have access to fewer resources and less speaking time in the legislature.

Gravelle said the party will need to rely on the basic resources provided to them as legislators in the coming days to represent their constituents and fulfil critic duties in opposition.

Liberal core 'actually held'

Western University associate political science professor Cristine de Clercy said while on the surface the election results are devastating for the Liberals, popular support for the party still gives a new leader something to build on.

"The Liberal core actually held," she said. "An awful lot of people voted for Liberal candidates and some of those people were elected. And a lot of Ontarians voted for the Liberal party knowing that their Liberal candidate was going to be defeated. They still voted Liberal anyway."

De Clercy said the party will now have to get down to the hard, unglamorous work of being an opposition party.

"The new leader will have to teach them how to be in the opposition benches," she said. "This is going to be terra incognita. They won't know how to function really in this role and it's an important role to help rebuild the party."

Ontario transitions over to a Progressive Conservative government on June 29.