Concerns remain on workplace bill: Greens

The fate of reforms to the country's industrial relations laws remains in the balance, with the Greens holding lingering concerns with the legislation.

Negotiations between the Greens and the government are continuing, ahead of the workplace laws being debated in the Senate later this month.

The laws, which would allow for multi-employer bargaining, passed the lower house last week.

The government said it wants to pass the laws by the end of the year but there are just two sitting weeks remaining before parliament rises for the summer break.

In order for the bill to pass the Senate, it will need the support of all 12 Greens senators and at least one crossbencher.

Greens leader Adam Bandt said regular talks were still taking place with the government.

While Mr Bandt said there were many elements of the laws he liked, including abolishing the construction industry watchdog, he hoped parts of the laws would change when the bill is introduced to the Senate.

"We are still concerned there are some elements of the bill that may allow some workers to go backwards," he told reporters in Melbourne on Monday.

"I don't think that's the government's intention. We raised those matters with the government privately, and we're hopeful that we'll see some changes when the bill comes before the Senate."

Mr Bandt said while there were parts of the bill he wanted to change, reforms to industrial relations in Australia were overdue.

"The industrial relations system in this country is broken, but we're hopeful the government as already taken on board a few of our concerns so far," he said.

Details of the bill are being examined by a Senate committee, with its final report expected to be handed down later this month.

At a hearing on Monday, the inquiry was told elements surrounding multi-employer bargaining still lacked clarity.

Professor Andrew Stewart from the University of Adelaide, who specialises in employment law, said it was not clear what counted as a common interest for businesses looking to bargain together.

He also said there would be unintended consequences following on from changes to the "better off overall" test.

"My fear is that it would complicate the approval process and it could even open up opportunities for workers to be employed on sub-award conditions," he told the inquiry.

"It's a drafting mistake which I believe needs to be corrected."