The government still appears on track to win support from the Senate crossbench to pass its media deregulation changes, which could trigger a round of major media mergers.

Key Senate crossbencher Nick Xenophon on Wednesday said he would not support legislation, to be introduced by the government as part of a deal with One Nation, to insert the words "fair and balanced" into the ABC charter or force the ABC to publish the salaries of all employees paid over $200,000 a year.

Both changes require approval separate to the government's media ownership bill and would fail to pass if Labor, the Greens and the Nick Xenophon Team combine to vote them down in the Senate.

Labor communications spokeswoman Michelle Rowland said it was "staggering" the ABC would cut a deal with One Nation to rewrite the ABC charter.

"Is the requirement for 'fair' and 'balanced' coverage designed to give voice to white supremacists, holocaust deniers, climate change sceptics and anti-vaxxers?" she asked.

One Nation senator Malcolm Roberts said it was only fair the ABC give more air time to vaccination sceptics given it gives prominent coverage to other "extremists", such as the Greens.

The ABC charter already requires its reporting to be "accurate and impartial".

Senator Xenophon said: "I cannot see the need for the so-called 'fair and balanced' test.

"What that would mean to the ABC, in terms of the way it could fearlessly report issues ... really concerns me.

"This talk of the ABC being subject to further restrictions and for ABC staff to have their salaries published, that would be quite unprecedented and I think put the ABC at a real disadvantage with commercial broadcasters."

ABC managing director Michelle Guthrie declined to comment on the government's decision to cut a deal with One Nation on the ABC charter.

One Nation's other key negotiating demand - an inquiry into whether the ABC is encroaching onto the turf of commercial operators - will not require legislation.

In a speech in Parliament House on Wednesday night, ABC chairman Justin Milne said the claim from commercial broadcasters that the ABC was venturing beyond its remit "couldn't be further from the truth".

But he indicated support for the government's media ownership changes, saying the "two-out-of-three rule" - which restricts media companies from controlling a newspaper, radio station and television network in the same market - was "outdated" and should be scrapped.

Abolishing the rule would allow Fairfax Media to merge with Channel Nine or News Corp Australia with Channel Ten.

Senator Xenophon said he was still in negotiations with the Communications Minister Mitch Fifield to extract more concessions including tax breaks for small media outlets to allow them to expand their operations and hire more staff.

He said hoped the matter would be dealt with this week but was willing to continue negotiating if the government did not go far enough to meet his demands.

ABC staff-elected director Matt Peacock said: "Politicians should realise the ABC should not be used as a bargaining chip - it is a national institution that is trusted by more than 80 per cent of Australians.

"Staff should not be intimidated by the continual attacks on the ABC and should maintain their commitment to fearless journalism in programs such as Four Corners as the ABC charter calls for."

High-profile ABC presenters said disclosing their salaries would be misleading given commercial media hosts are often paid far more than they are.

"Lisa Wilkinson would be earning far more than Leigh Sales," an ABC presenter, who requested anonymity, said.

"A salary of $220,000 sounds like a lot, but not compared to what the commercial networks pay.

"Presenters there can earn three, four, five times as much as we do."

Another presenter said publishing salaries would be a "painful and detrimental invasion of privacy", but could help expose the pay gap between male and female presenters doing similar jobs.