Ross Garnaut said his Papua New Guinea travel ban has been a "low point" in Australian diplomacy.

Professor Garnaut resigned as chairman of Ok Tedi Mining Ltd last week after being banned from PNG by Prime Minister Peter O'Neill.

He is concerned the ban may set a precedent that would introduce a major "new element of sovereign risk, a barrier to PNG development and a recurring volcano in bilateral relations".

"My ban was a low point for Australian diplomacy," the Australian government's climate change adviser told ABC radio on Monday.

"It's a low point for PNG development and a low point for PNG democracy."

He has called for Australia to push for a bilateral or regional agreement to prevent the situation recurring.

"The important thing now is that it never happens again - that a government never again seeks to exercise leverage against legitimate international corporate interests through the misuse of immigration powers," Prof Garnaut said.

In November 2012, the PNG foreign affairs department was instructed to prevent Prof Garnaut from entering the country after the prime minister said the Australian was no longer welcome and accused him of insulting the nation's leaders.

During a grievance debate in PNG parliament a few days before the November decision, Mr O'Neill referred to a report in The Australian newspaper quoting Prof Garnaut as saying that with the accumulation of wealth in PNG it was "tempting for political figures to think of better ways of using it right now rather than putting it into long-term development".

Mr O'Neill has previously said Prof Garnaut, who until recently was also chairman of the PNG Sustainable Development Fund (PNGSDF) trust, would not be allowed back in until control of the Ok Tedi mine was given back to the PNG people.

The $1.4 billion charitable trust was given ownership of the Ok Tedi mine, in PNG's Western Province, by BHP Billiton.

Mr O'Neill claims BHP is running PNGSDF by remote control and questioned whether the 37-year-old nation had benefited from the project.

The Department of Foreign Affairs defended its diplomatic efforts on the issue, saying the Australian commissioner in Port Moresby had raised the issue three times with senior PNG government officials.

A DFAT spokeswoman said Australia strongly supported freedom of expression and the right to hold an opinion without interference.

"Ultimately it is for the Papua New Guinea government to determine who is permitted to visit that country," the spokeswoman said.

Pic: Greg Burke, The West Australian.