The federal government has made concessions on its contentious industrial relations legislation in a bid to get it through the parliament before Christmas.

Workplace Relations Minister Tony Burke has agreed to amend the bill amid ongoing talks with business groups who remain firmly opposed to an expansion of multi-employer bargaining – the most contentious element of the wide-ranging legislation.

Despite the concessions, business representatives remain unconvinced, describing parts of the bill as "bad policy" and calling for the passage of legislation to be delayed until it can be thoroughly scrutinised by the Senate.

Mr Burke said the government will make it a requirement that a majority of employees within each workplace would need to vote in support of multi-employer bargaining before an agreement can take place.

"One of the concerns, which was a reasonable concern, was… one employer where there's a heap of staff, another where it's much smaller numbers, and effectively, the bigger workplaces overwhelming the vote of the smaller one," Mr Burke told Sky News on Sunday.

"It'll be changed, so that to be part of an agreement, where you're getting a majority of the staff, it's employer by employer where that's counted.

"If your vote against any of the stages at that business level, then you're not part of it."

Labor wants the bill passed this year, arguing the proposed changes will help drive up wages and make the enterprise bargaining system fairer for workers.

Pocock calls for more time to consider bill

While the government has the numbers to get the bill through the lower house, it faces some hurdles in the Senate, with key crossbenchers calling for more time to review the bill while expressing concern about the breadth of the changes and potential unintended consequences.

Independent ACT senator David Pocock said the government should split the bill to allow for the passage of non-controversial changes while further time and consideration were given to the more contentious elements.

"I do not want to stand in the way of low-paid workers, especially in highly feminised industries, getting a pay rise," he said.

"I do want to make sure we get this legislation right.

"The bill was introduced just over a week ago and already we've seen a number of significant changes flagged by the government.

"This says to me that we need more time."

Senator Pocock said the legislation had been "very rushed" and he was concerned about the lack of time given to the Senate to conduct consultations.

"This is not about delaying, it is about having the minimum amount of time needed to do the job I've been elected to do properly," Senator Pocock said.

"I want to work constructively with the government to make sure this bill does get wages moving, improves equality in the workplace and also avoids any unintended consequences."

However, the government faces some hurdles in the Senate, with key crossbenchers calling for more time to review the bill while expressing concern about the breadth of the changes and potential unintended consequences.