"Oppose and delay are the two weapons that an opposition has," Mr Mallard said yesterday. "Delay can draw attention to the degree of anxiety that we have around a particular piece of legislation."
Supporters of the bill say student unions are the only ones in the country which still have compulsory membership, and are often organised by political activists who run partisan campaigns which don't represent the views of members.
Opponents argue that unions and associations will perish without compulsory membership because hard-up students won't pay fees, and valuable roles such as advocacy will be lost.
Mr Mallard, a 27-year veteran of Parliament, said he couldn't recall a members bill being filibustered for so long since the Homosexual Law Reform Bill in 1986.
Given that they believed many National MPs were not strongly supportive of the bill, Labour had hoped that its delaying tactics would allow a compromise to emerge, but had now given up on that prospect.
Although there are just three days on which the bill can be debated before the election and it needs at least two to pass, "the way it's shaping up the bill will pass before then", Mr Mallard said.
He believed the Government would take action to ensure that, which could include taking over the bill itself or having it heard under urgency. additional reporting NZPA