The federal government came under fire from the opposition parties on everything from corporate tax cuts to military spending Monday, as Parliament returned from summer break with a rowdy session of question period.

Despite pledges last week to work together in a spirit of collegiality, MPs took swipes at each other, with the prime minister defending his government's position on crime, the economy and military spending.

Liberal Leader Michael Ignatieff fired the first salvos, asking the government about corporate tax cuts and the $1 billion price tag of the recent G8 and G20 summits.

"(The prime minister is) going to have to explain the waste to Canadians -- a billion on a G8/G20 Summit photo opportunity, $10 (billion) to $13 billion on prisons when crime is actually declining," Ignatieff said. "He's going to have to explain these priorities to Canadians. He's going to have to explain why it is that it makes sense to give corporations a $6 billion tax cut when we're in a $54 billion deficit."

Ignatieff also asked about Ottawa's proposal to purchase stealth fighter jets in a deal that could total $16 billion with maintenance and other costs factored in.

"I have no difficulty explaining that this government's priority when it comes to crime is having criminals in prison, not out on the street," Harper said. "I have no difficulty explaining to Canadians that when we send our men and women into dangerous military situations, we are prepared to give them the equipment they need. Mr. Speaker, I have no difficulty explaining to Canadians when we're in the middle of a recession, we don't talk about hiking tax on businesses or anybody else."

The last session before an election?

Recent polls have shown the Liberals and Conservatives to be nearly neck and neck, but both say there is little appetite for a fall election.

Instead, both parties appear to be trying to build support in preparation for an election down the road, possibly in the spring.

Ignatieff's summer bus tour, despite its rocky start, has been hailed a success, reviving his lagging political fortunes and stoking those election fires.

He says speaking to Canadians over the summer will guide his party's priorities in the fall session.

"I'll try to go into (the House) and ask the questions that Canadians want answered," he told CTV's Power Play Monday.

"Canadians are worried about pensions, retirement security, jobs, education for their kids, homecare for their elderly relatives -- basic, basic stuff. And we just think the government hasn't gotten those priorities."

The prime minister's decision to make Conservative MP John Baird government house leader took many by surprise as it's the house leader's job to work with the opposition parties on deal-making. Baird has been known as the Tory's top attack dog in previous sessions, but he says he works well with opposition MPs.

"I thought today was demonstrably more civil than in a long time," Baird said on Power Play. "We've got three months in this fall session; let's try to get some work done for the Canadian people."

Baird said the Tories' priorities this fall will be the economy and combating crime and terrorism.

NDP Leader Jack Layton said the government is wasting taxpayers' money, noting the purchase of the fighter jets and cuts to corporate taxes for banks and oil companies.

"They don't need corporate tax reductions for those big, profitable companies," he said on Power Play.

But Layton also noted that civility in the House Monday was "a little better than normal."

The first battle

During question period, MPs also haggled over the contentious issue of the long-gun registry, two days before they are to vote on a bill that would kill it for good.

Layton asked why the government doesn't seek a solution to amend the registry to make it more palatable to both urban and rural voters.

Before he asked that question, Layton was heckled by Tory MPs over comments calling for an end to "U.S.-style, wedge politics," prompting him to quip: "Now I see the new commitment to decorum is working out well on the government side over here Mr. Speaker."

"Obviously the smooth functioning of Parliament depends on the willingness of all of its members," the prime minister shot back before taking a dig at NDP MPs who in recent days have declared their intention to vote against the bill when they had previously supported it.

Harper said Tory MPs who have told their constituents they will vote to kill the registry have done just that. "Mr. Speaker I would encourage the NDP and the members of the NDP to implement the same level of integrity."

NDP MP Peter Stoffer was the latest in his party to change his tune on the gun registry and now says he wants to save it.

A longtime critic of the registry, he says he thinks it is flawed but changed his decision after consulting his constituents.

One of the Opposition's main lines of attack on the Conservatives is that while they promote themselves as the law-and-order party, they are against the gun registry, which most police organizations support.

Baird said there is no contradiction.

"We think we are better going after people who use guns in the commission of offences than to make criminals of duck hunters and sportsmen," he said. "The reality is the people that use guns for offences, don't register them."