Media blackouts, mobile polling booths and donation caps are all on the table to get the Indigenous voice over the line.

The Albanese government is preparing to make changes to how the referendum is conducted in the hope of garnering support from across parliament.

The amendments include a broadcasting blackout, which will restrict TV advertisements up to three days before the vote.

The threshold for disclosing donations will be frozen at $15,200, scrutineer numbers boosted and mobile polling periods extended in remote areas.

The changes won't be enough to convince the coalition but could clinch support from the Greens and some independents.

The coalition wants "yes" and "no" campaign organisations set up to provide information, with equal public funding for both sides, but Labor is not budging.

Indigenous Australians Minister Linda Burney said the government had already made a significant concession by agreeing to send households pamphlets outlining both cases.

Attorney-General Mark Dreyfus said the Liberal Party could continue to argue for public funding while backing the bill.

"There is still time to support constitutional recognition, still time to support the voice," he told parliament.

"I urge members of the opposition to keep an open mind and an open heart when it comes to this referendum."

The Liberal Party is yet to decide whether to allow a conscience vote on the referendum but the Nationals oppose the voice.

Greens leader in the Senate Larissa Waters said her party would introduce amendments to the upper house including on-the-day enrolment and the phone voting COVID-19 election measure.

"We want to give the voice referendum the greatest chance of success," she said.

"The Greens will consider any amendments to ensure information resources outlining the 'yes' and 'no' cases are fair, accurate and respectful."

A member of the Indigenous voice working group says the coalition is "playing games" over the way the referendum will operate.

Marcus Stewart, a member of the Referendum Working Group, said the coalition's demands were unreasonable.

"Once again, we are witness to a thinly veiled attempt to cast doubt in the minds of Australian voters," he told AAP.

"Access to factual information will be key to the success of the referendum and the Albanese government is playing their part by ensuring every voter can access this information through the civics education program.

"This tactic from the coalition is evidence they are playing political games."