The Liberal party is bringing out the big guns as the May 2 election approaches, with two former prime ministers lending their support to Michael Ignatieff's campaign.

Paul Martin addressed a cheering crowd alongside Ignatieff at a Liberal campaign rally in Edmonton on Saturday evening, attacking the Tories' fiscal record and election platform.

"You want to know what the Conservative legacy is? It's the biggest spending, it's the highest debt and it's the highest deficit in Canadian history," Martin said to applause.

"But don't worry. Liberals have had a lot of experience cleaning up the messes created by Conservative governments, and we'll fix it up again."

Martin also charged that the Conservatives' proposed plan to eliminate the deficit will require major service cuts.

"The one area that's clearly in danger, that's going to suffer in that, is in fact the health-care budget -- because Stephen Harper has said unequivocally that he does not think that the Canada Health Act or that health care is a federal responsibility," he said.

Martin is expected to travel to Vancouver join Ignatieff at campaign stops in Vancouver on Sunday.

The Liberals hope to steal seats from the Conservatives in both the Edmonton Centre riding formerly held by Liberal MP Anne McLellan, and in Vancouver South, where Liberal MP Ujjal Dosanjh won with just 20 votes over Conservative candidate Wai Young in 2008.

Closer to election day, Ignatieff will be joined by former prime minister Jean Chretien at an event in Toronto.

Elsewhere on the campaign trail, Prime Minister Stephen Harper defended bonuses for political staffers, saying they are in-line with "across the board" raises in the civil service, even as the government eyes budget cuts to the public sector.

"The pay raises we're talking about are pay raises across the board," Harper said.

"They're not for political staffers. These are government employee pay raises and our political staffers are simply tied to those."

In one case, bonuses drove up a ministerial staffer's annual income by $35,000, resulting in a final salary of $190,000.

But Harper said that new Treasury Board guidelines will effectively tie political staffers' income to the civil service. He added that overall ministerial budgets will be cut by 11 per cent.

The new guidelines went into effect in April and aren't tied to the current electoral platform.

Harper was asked about the payment plan for ministerial staffers during a campaign stop in Vancouver Saturday, where he also spoke about new proposals to crack down on drug use by prisoners in federal penitentiaries and other crime bills that would increase penalties on offenders convicted on child sex crimes.

Speaking at a rally, Harper said a Conservative government would expand measures that eliminated sentencing discounts for multiple murderers to include child sex offenders who receive multiple convictions.

Harper said the Conservatives would also double the victim surcharge fee for sex offenders and make it mandatory. Currently judges have discretion to waive the fee.

And the Conservatives would crack down on drug use in prisons to ensure all prisoners are tested at least once per year. Positive tests would result in additional charges.

The measures, Harper said, ensure that victims' rights will take priority over those of their attackers.

Meanwhile, NDP Leader Jack Layton was campaigning in Newfoundland on Saturday in the St. John's South-Mount Pearl riding held by Liberal MP Siobhan Coady. In 2008 she won the race by less than 1,000 votes over the NDP candidate.

Layton pledged an NDP government would invest in renewable energy sources, create jobs and give back to families.

He said the NDP offers a government Newfoundlanders can trust after being let down by both the Conservatives and the Liberals.

Layton also took aim at Liberal Leader Michael Ignatieff, saying he has a record of either not showing up for votes in the House of Commons, or supporting Conservative proposals -- including the elimination of equalization payments to Newfoundland and Labrador.

"Friends, Mr. Ignatieff had his chance to stand up for Newfoundland and Labrador and he blew it," Layton said.