Prime Minister Stephen Harper's office faced more pointed questions in the House of Commons Wednesday over what he or his office knew about his former chief of staff's arrangement to repay expenses claimed by Senator Mike Duffy, a day after a Senate committee voted to refer the matter to the RCMP.

NDP Leader Tom Mulcair used his party's second round in question period to probe whether Nigel Wright would receive a severance package for offering his resignation.

"Under the law, how much severance pay is Nigel Wright entitled to? Would it just happen to be approximately $90,000 [the amount of the "gift" cheque he gave to Duffy]?"

Harper said Wright will receive "only the payments to which he is entitled under the law and nothing more."

The prime minister pointed out that the government is required to "pay certain amounts under law, such as certain accumulated vacation pay." But Wright will be paid only that, Harper said.

The prime minister's office said later that it is consulting before any money is paid out to ensure only what is absolutely required is provided, ruling out any extra separation pay arrangements.

It was the second straight day that NDP Leader Tom Mulcair asked most of his party's allotted questions and kept them short and focused. He started by asking Harper about an email in which Duffy is reported to have said that he was ordered by the Prime Minister's Office to stay silent on the issue of his expenses.

"Who in the Prime Minister's Office has a copy of that email?" Mulcair asked.

"Mr. Speaker, this is an email, I understand, of Mr. Duffy, a former Conservative senator ... As we know well, the activities of Mr. Duffy are being looked into by the appropriate authorities and of course any and all information we have will be shared with the authorities," Harper replied.

Liberal Leader Justin Trudeau asked when Harper learned of the repayment of Duffy's expenses by Nigel Wright, who has since resigned as Harper's chief of staff. Trudeau asked how the prime minister could not have known about the arrangement until May 15 if media had called his office the day before.

"As I've said repeatedly, as soon as this information was conveyed to me by the former chief of staff, I immediately insisted he go to the appropriate authorities, and the information be made public," Harper replied.

Harper repeatedly turned the questions back on Mulcair and Trudeau, pointing seven times to Mulcair's recent revelation that he waited 17 years to talk to police about a possible bribe attempt by the mayor of Laval, Que., and suggesting Trudeau was refusing to deal with allegations published by CBC News that the husband of a Liberal Senator has $1.8 million in offshore accounts.

Wallin repayments a preview?

Later in question period, Liberal Dominic LeBlanc reminded the Commons that despite Harper's assurances in February that he had personally reviewed Senator Pamela Wallin's travel expenses and found them to be perfectly fine, things appear different now.

Wallin has reimbursed tens of thousands of dollars of expenses "that she must have thought were inappropriate or perhaps fraudulent," LeBlanc said.

CBC News has confirmed that the expenses repaid by Wallin to date exceed $40,000 and may not stop there.

Heritage Minister James Moore replied that "independent authorities are looking into these matters." Despite the fact that Wallin's repayments have already begun, the Senate-initiated audit of Wallin's expense claims has yet to report its findings.

Before question period, MPs on Parliament Hill were still reacting to news that Duffy's expense claims problems are more widespread and more questionable than first revealed in the reports from the accounting firm Deloitte and the Senate on May 9.

A Tuesday evening meeting of the Senate's committee on internal economy also revived questions about why two Conservative senators edited the May 9 report on Duffy in his favour, taking out language that stated Senate expense rules are "clear" and "unambiguous."

Conservative MP Brent Rathgeber said he has received many calls and emails from constituents upset about Duffy's expense claims, and asked how the senator was able to make so many ineligible claims.

But Rathgeber said he believed Harper's repeated assertions yesterday in the House of Commons that he did not know about the $90,000 cheque from Wright to pay off Duffy's ineligible expenses — although he wondered how the prime minister could not have known.

Speaking outside the NDP caucus room in the House of Commons, Mulcair said there's a lot of questions Harper has refused to answer.

"We're going to continue to hold his feet to the fire," he said.

Mulcair noted that during Tuesday's question period, the prime minister did not directly answer whether he discussed the cheque Wright wrote to Duffy with his cabinet.

"[Harper] would have us believe this was just between Nigel Wright and Mike Duffy," Mulcair said, adding that to his mind there had to have been other people involved.

Asked if the fact Senate staff had refused to pay out half of Duffy's claims should have raised red flags, Mulcair replied,"If someone's expense claims are being consistently rejected, that sets off a yellow light on the dashboard, if not a red one."

Mulcair said the Senate costs Canadians $100 million a year, and that Harper has never been serious about Senate reform.

Mulcair was asked twice if meetings about MPs' expenses should be made public, as the Senate meeting was Tuesday.

"Two totally different circumstances," he replied, saying that the auditor general has found no problems with the way MPs account for their expenses. The Senate, he said, is "unaccountable."

Trudeau pressed on openness for MPs

Trudeau told reporters that the prime minister's preferred path is "to block, to obfuscate," and wondered again why it took five days for Wright to resign after he told Harper about the payment to Duffy.

Reporters pressed Trudeau whether all senators should now undergo audits of their expenses. Trudeau eventually said he agreed this should be done.

He was also asked, since the Senate meeting Tuesday was opened up to the media, shouldn't MPs' meetings about their expenses cease being held behind closed doors.

Opening up expense accounts was desirable, Trudeau said when pressed, but added, "There will always be a need for an approach that's responsible, but not open to fear mongering."

Conservative MPs defended the prime minister as they left their Wednesday caucus meeting.

"The PM had nothing to do with this. I think that's very clear," said Sault Ste. Marie MP Brian Hayes.

"The prime minister was truthful. He was honest and told us exactly what happened," echoed Jay Aspin, MP for Nipissing-Timiskaming.

But NDP MP and ethics critic Charlie Angus said there was evidence of a coverup.

"For crying out loud, even the senators are saying this stinks to high heaven. They said there was major inappropriate spending by Mike Duffy. Now Nigel Wright was in contact with the Senate. They were talking about what was going on, so certainly the prime minister must have known that these were really dodgy expense claims and then the secret cheque was cut to cover all this up," Angus said.

With the Senate calling in the police, how can the prime minister continue to act as if the cheque from Wright was "no big deal," Angus asked.

Scrutinize top 10 spenders: LeBreton

Speaking to reporters outside the Conservative caucus room Wednesday, government Senate leader Marjory LeBreton said she believes that the top 10 spenders in the Senate should be audited annually, although she didn't specify who would conduct the audits or whether they would be made public.

"This has been going on for years. I know many Liberal senators that represented regions that had permanent homes in Ottawa. Where do you start?" she said.

She was referring to the practice of claiming a home at least 100 kilometres outside of Ottawa as a primary residence even though in reality the senator's permanent abode is in the capital.

Of the four senators who must repay money for doing exactly what LeBreton describes, three were appointed as Conservatives on the advice of Harper.

On Tuesday, the clerk of the Senate as well as the Senate director of finances told the specially convened meeting Duffy had tried to claim per diems and related expenses for 18 days in August 2011, when he was at his cottage in P.E.I.

In all, of 49 claims Duffy submitted over a one-year period, only 25 were paid out. The rest were disallowed by Senate administration staff because it was determined he was not in Ottawa on Senate business as he claimed.

The Senate committee voted unanimously to refer Duffy's claims to the RCMP, and added a request that the $90,000 cheque given to Duffy by the prime minister's top aide be examined as well.

The committee also voted to restore the language in the May 9 report on Duffy. Senators David Tkachuk and Carolyn Stewart Olsen who were responsible for redacting the language voted last night to put it back in the report.