OTTAWA -- The Harper government has made another small concession to allow greater scrutiny of its massive, omnibus budget implementation bill.

It agreed to a Liberal proposal Wednesday to allow nine House of Commons committees -- not just the finance committee -- to examine different aspects of the 400-plus-page bill, which makes changes to some 60 pieces of legislation.

But Liberal finance critic Scott Brison said the concession should not be interpreted as respect for parliamentary democracy.

"This is a thimbleful of respect for Parliament in a sea of contempt."

Brison noted that MPs will still be forced to make a single vote on the bill, even though it contains a diverse collection of measures, some of which opposition parties oppose, others of which they support.

This is the second omnibus bill the Conservatives have introduced to implement last March's budget. The first mammoth bill last spring triggered an opposition filibuster that brought Parliament to a virtual standstill for several days.

Interim Liberal Leader Bob Rae refused to rule out employing similar tactics to stall the second bill. He said his party's approach will depend on the government's willingness to accept amendments.

On that score, the government signalled Wednesday that it's not likely to accept any opposition amendments to the bill.

NDP environment critic Megan Leslie asked in the Commons whether the study by committees will be strictly "look but don't touch" or whether the bill can be amended.

Finance Minister Jim Flaherty responded by noting that last week the government agreed to hive off a portion of the bill dealing with reform of MPs' lucrative pension plan. That portion was immediately passed, with unanimous support.

Flaherty said the government would look at hiving off any other portions that opposition parties care to pass unanimously. He made no mention of accepting amendments to parts of the bill for which there is no unanimous support.

NDP Leader Tom Mulcair said there are some things the NDP would agree to quickly pass, such as tax breaks for small business. But he doubted the Conservatives would agree.

"The problem with the Conservatives is it's always a take it or leave it approach," Mulcair said.

Rae said there are measures in the bill that Liberals support but "there are very (much) more elements" that they oppose.

The bill makes changes to everything from the Indian Act and Canadian Labour Code to the Canada Shipping Act. Among other things, it kills off independent tribunals that examine such things as employment insurance premiums and hazardous materials in the workplace.

Most controversially, the bill continues the government's agenda to reduce regulatory obstacles to development, sharply reducing project approvals required under the Navigable Waters Protection Act and making further changes to environmental assessment laws.

It exempts entirely the planned new Windsor-Detroit bridge from a range of federal laws under which permits, approvals or authorizations would normally be required.