MPs will put in a full day on the Hill before starting dozens of rounds of voting Wednesday evening on a 425-page budget bill that would change more than 70 laws.
The House is expected to move to voting on more than 800 changes proposed by opposition MPs by early evening. MPs can get through about six votes every hour.
Due to some procedural votes introduced in the afternoon, voting is not expected to get underway until about 8 p.m. ET Wednesday.
On Monday, House of Commons Speaker Andrew Scheer grouped similar amendments together to streamline the voting process.
NDP Leader Tom Mulcair said not all his MPs will be in the House at the same time for the votes. The House leader's office and the whip's office are working out a rotation, he said.
"That's not the best use of our resources, but we'll be there, the majority of MPs, at all times" Mulcair said.
Asked about the changes to environmental law proposed in the budget, Mulcair compared Environment Minister Peter Kent to a clueless journalist portrayed by comedian Will Ferrell in the movie Anchorman.
"We have Mr. Kent who simply reads whatever is in front of him. He reminds me of Will Farrell’s character Ron Burgandy," Mulcair said.
"I mean, he’ll just read whatever it says on his piece of paper. And he doesn’t even have to understand, it doesn’t matter, he’ll stand up and say everything’s going well, and they’ll just keep repeating those lines."
Finance Minister Jim Flaherty says the opposition is using the budget for political posturing.
"We've had more than 50 hours in the finance committee," he said. "If they have something serious to say, it ought to have been said by now. Instead it's just political posturing. And I'm a politician, and I know that it's easy for politicians to say that, but I'm also the finance minister, I know what's going on in the world, and it's a matter of substantial concerns."
The House passed a motion earlier this week to allow sittings until midnight as the summer break approaches.