NDP Leader Thomas Mulcair says his party is ready for a fight if the Conservatives' budget focuses on service cuts, not job creation.

Mulcair led his first formal Parliament Hill caucus meeting Wednesday since winning the NDP leadership on the weekend.

He used the occasion to rally the troops to prepare for the Conservative government's budget, which will be tabled Thursday.

"Here we are, once again more united than ever before and ready to roll up our sleeves and stand up and face off against Stephen Harper's right-wing policies," he said to applause.

Mulcair said the process of defeating the Conservatives and putting the NDP into office begins with this budget.

During question period Wednesday, the NDP leader used the opportunity to slam potential cuts to the public service.

"These cuts will hurt Canadians by denying them the services that they need . . . they will hurt the economy," he said.

Foreign Minister John Baird responded, saying Finance Minister Jim Flaherty will deliver a budget focused on job creation.

"When it comes to middle-class families, they can count on this government to support their key priorities," Baird said.

During his caucus meeting, Mulcair said budgets require tough choices but Harper couldn't be trusted to make the correct ones.

"Mr. Harper has an opportunity to give some respite to the middle class and to invest in job creation. He can protect essential services that Canadians rely on. I hope that that's what he is going to do, but we shouldn't be dreaming in Technicolor, especially with him," he said.

Mulcair was cheered throughout his speech by his caucus, especially when he welcomed Craig Scott, who won the byelection to replace Jack Layton in the Toronto-Danforth riding.