Liberal Leader Justin Trudeau has suspended ethics critic Scott Andrews and Quebec MP Massimo Pacetti from the party's caucus after two New Democrat MPs alleged they were harassed.

Trudeau was informed last week of allegations against the MPs, according to a letter distributed by party whip Judy Foote. The party referred the allegations to House Speaker Andrew Scheer for an independent investigation.

Both MPs deny the allegations, but have been suspended pending resolution.

The letter refers to the allegations being about "personal misconduct."

Like workplaces across this country, Parliament needs clear guidelines and procedures for dealing with allegations of serious personal misconduct of this nature. - Justin Trudeau, Liberal leader

Trudeau gave no additional details when questioned by reporters after the party's weekly caucus meeting. He didn't answer questions about whether the alleged misconduct was sexual harassment, when it happened, or the exact nature of the allegations.

"I am aware of how difficult it is for people to come forward. I believe strongly that those of us in positions of authority have a duty to act upon allegations of this nature," Trudeau said.

"It's 2014 — we have a duty to protect and encourage individuals in these situations to come forward. The action must be fair but decisive. It must be sensitive to all affected parties but, recognizing how difficult it is to do so, it must give the benefit of the doubt to those who come forward."

'Serious allegations'

Opposition Leader Tom Mulcair did not divulge the identities of the New Democrat MPs who have alleged they were harassed.

Everyone who works in these places has a right to be in a secure work environment free of harassment. - Tom Mulcair, NDP leader

He said he was saddened by "these serious allegations" and that it was incumbent on MPs from all parties to take them seriously.

He did not give the specific nature of the allegations.

"Here on Parliament Hill and in every workplace, women have a right to be in a secure work environment. Everyone who works in these places has a right to be in a secure work environment free of harassment," Mulcair said following a meeting with his caucus on Wednesday.

"We want to make sure that all parties work on these issues and I think it's something that we should do together to show that it is something on which we all agree."

Mulcair said he would not comment any further to respect the privacy of the NDP MPs.

He was flanked by MPs, including:

Ruth Ellen Brosseau, vice-chair of the NDP caucus​.

Mylène Freeman​, chair of the w omen's caucus.

Niki Ashton, the party's critic for status of women.

"For obvious reasons to respect the privacy of all concerned, I won't be making any other statements right now," Mulcair said.

Whip met with MPs making allegations

Trudeau said there's no process for dealing with this kind of situation.

"Like workplaces across this country, Parliament needs clear guidelines and procedures for dealing with allegations of serious personal misconduct of this nature," he said.

In her letter, Foote said she met on Oct. 29 with the whip of the caucus to which the two party members belonged, the day after Trudeau was made aware of the allegations.

One of the MPs alleging misconduct approached Trudeau directly, she writes.

Foote said she met with the MPs making the allegations on Oct. 30, and has spoken separately with Andrews and Pacetti.

"To my knowledge, there is no precedent or established process for dealing with a situation such as this," she wrote. "The House of Commons has a process for administration employees to address allegations of misconduct in the workplace, but there is no established process for complaints between members."

The Liberal Party is asking Scheer to refer the matter to the Board of Internal Economy, a committee of MPs from all parties.

In response to the letter by Foote, the office for the Speaker issued a a written statement saying Scheer was taking the matter "very seriously."

"He has directed the House Administration to make available all internal resources to the individuals involved. The House Administration stands ready to provide assistance as required.

"The Speaker has also directed that the matter be taken up at the Board of Internal Economy, at the earliest available opportunity," the statement from the House of Commons Speaker said. The BOIE is a secretive committee made up of MPs from all parties.

Liberal MPs deny allegations

In a written statement released on Wednesday afternoon, Andrews appeared to support the idea of an "independent third-party" investigation, as requested by Foote.

"I encourage the Speaker or Board of Internal Economy to establish an appropriate process without delay," he said.

"I intend to fully co-operate with answering any and all questions from an independent, third-party investigator. However, it would not be appropriate for me to answer questions prior to a non-partisan process being established, and being provided with the specifics of the allegation."

Even so, he said he was "confident" that the investigation "will find that no harassment has occurred."

Pacetti ​said in a written statement that while he has not been informed of the specific allegations against him, Trudeau told him he was suspended over allegations of "personal misconduct."

"I have not been provided with the specific details of the allegations that led to this suspension.

"Scheer has been asked to conduct an independent investigation, with which I intend to co-operate fully, and which I am confident will exonerate me," Pacetti said.

Andrews was first elected as the MP for the Newfoundland riding of Avalon in 2008. Pacetti has represented the Quebec riding of Saint-Leonard—Saint-Michel since 2002.