Hours after Prime Minister Justin Trudeau and his Liberal cabinet were sworn into office, NDP Leader Tom Mulcair met with his caucus on Parliament Hill in his first public appearance since the election.

After being sent back to third-party status on Oct. 19, NDP MPs returned to Parliament Hill in Ottawa on Wednesday, albeit with a much smaller caucus. They met in a smaller space located in the basement of Parliament Hill.

The NDP took a significant hit on election night, particularly in Quebec, where in 2011, the Orange Wave sent the party to Official Opposition status for the first time in history.

At the dissolution of Parliament earlier this year, the NDP held a total of 95 seats but on election night, the caucus was reduced to 44 members.

Speaking to his caucus on Wednesday, Mulcair took responsibility for the loss of seats during the election.

"This is the second-largest caucus in our party's history," Mulcair said. "Let's never forget that, but I know and we all know that's not enough."

The NDP leader also started the work of guiding his party forward.

“What was most important for me today was to remind people of what we’ve accomplished,†Mulcair said. “We had set out to get rid of Stephen Harper’s Conservatives.â€

Mulcair also said that he’s “committed to overseeing†a process to find out what happened on election night, and lead his party to government in four years’ time.

“I want an unvarnished, open, complete look at what happened and will report back to you and to all members of the party on that,†Mulcair said.

However, Mulcair must first pass an NDP leadership review set for spring 2016.

Meanwhile, the Conservatives, which were reduced to Opposition party status after nearly 10 years as government, are also back in Ottawa for a meeting set for Thursday.

They are preparing to replace Stephen Harper as leader. The Conservative Party announced on Election Night that Harper would be stepping down as leader of the Conservatives.

Former Foreign Affairs Minister Rob Nicholson, who is among those throwing in their names to lead the party in the interim, said the party is regrouping.

“The very fact that we have seven or eight people there to put their name forward shows the enthusiasm within our caucus and determination of our caucus to be part of the future,†Nicholson said.

Former Transport Minister and re-elected Conservative MP Lisa Raitt praised some of Trudeau’s choices on Thursday, including his decision for gender parity within cabinet.

“You know, those women would make it into cabinet on merit alone,†Raitt said.

But both the NDP and Conservatives say that the upbeat tone of the day at Rideau Hall is one thing that they will be there to ensure the Liberals deliver.

With a report by CTV’s Genevieve Beauchemin