Opposition parties outlined Thursday some of the tactics they're planning on using to pick apart the government's massive budget bill.

The NDP said it will move more than 20 motions at various House of Commons committees to try to put Bill C-38 under a microscope and provide more oversight on the changes it seeks to make to dozens of laws.

"We are demanding that Conservatives do the right thing and allow committees and Canadians to study the impacts of this bill. Also, they must allow us to do our work in public and not in camera. The abuse of this tool is an affront to democratic principles," NDP House leader Nathan Cullen told reporters Thursday.

Conservatives have been using their majority on several committees in recent months to force proceedings behind closed doors.

Cullen said the NDP is trying to make Canadians aware of measures in the bill, such as raising the eligibility age for Old Age Security and overhauling environmental assessment rules, that were never mentioned by the Conservatives during last spring's election campaign.

"There was no mandate given to this government to do the things that it's doing and by cramming it into a Trojan horse bill it is ignoring the will of Parliament and the accountability that Parliament demands," he said.

Deputy NDP leader Megan Leslie is moving a motion at the environment committee Thursday afternoon to study the portions of the bill related to the environment.

"It's time for a real discussion (of) what's happening with this budget bill, in particular around the environment issues," Leslie told reporters. "A third of this bill is about gutting our environment regulations. We need to have a real discussion at the proper committee."

As it stands, the budget bill will be studied at the finance committee once it passes second reading. The opposition complains the committee doesn't have the expertise to examine the wide range of measures that amend and repeal dozens of laws.

The government said it will establish a subcommittee to study the changes to environmental regulations, but the opposition parties aren't satisfied. They tried and failed to convince the government to divide the massive bill into smaller bills for study at the relevant committees.

Liberals may try to delete 700 clauses

Liberal House leader Marc Garneau said his party could try to stall the bill at the report stage after it has been studied by the finance committee.

He pointed out that amendments can be proposed that seek to delete clauses in the bill — and there are more than 700 clauses. That could mean hours upon hours of voting if the Liberals propose separate amendments to delete individual clauses.

"That is an option that the Liberal party is certainly examining at this point," Garneau said. The Liberals want to show the government that what they are doing is "profoundly anti-democratic," he said, adding that the bill will have "profound consequences."

"This is a bill frankly that is really abusing parliamentary democracy," said Garneau. "We have tools and we're going to use them."

Liberals have Green Party MP Elizabeth May on their side and would also be happy to talk to the NDP to align strategies, Garneau said.

"We all share the same concerns with respect to this bill," he said.

But the NDP wasn't keen on the Liberals' idea when Cullen was asked about it. He said the report stage won't come for another month and that talking about what to do then is conceding that nothing can be done now.

"We think there are other opportunities in the meantime where we can fight the government day in and day out and those are important opportunities for Canadians," he said.

Van Loan urges parties to act responsibly

Conservative House leader Peter Van Loan said the government is focused on delivering on its commitments.

Friday will be the last day of debate for the bill at second reading and Van Loan said it will have been the longest budget bill debate "in certainly the past two decades, probably ever."

"It's important that we make decisions," he said, adding that the global economy is still in a fragile state. He said Canadians want to see their MPs do work, not stall, and he hopes "parties will conduct themselves in a responsible fashion" that will allow MPs to make decisions that affect job creation and the economy.

"I think the NDP have discredited themselves by really not focusing on the substance of job creation and economic growth but instead on delay tactics," he said.

The NDP triggered a series of procedural delays Wednesday, just two hours after the government rejected the official Opposition's proposal to split the 400-plus-page bill into smaller chunks that could be scrutinized more closely.