Bishop calls for calm after PNG deaths

PNG police opened fire on a group of protesting students in the capital and there's report at least 15 had been wounded and four killed.

Foreign Affairs Minister Julie Bishop has called for calm amid reports PNG police shot students. (AAP)

Foreign Affairs Minister Julie Bishop has called for calm amid reports Papua New Guinea police shot dead four students marching on the country's parliament.

"We call on all sides for calm to de-escalate the tensions and certainly call on all sides to respect the peaceful and lawful right to protest. We will be monitoring the situation closely," she told reporters in Brisbane on Wednesday.

Ms Bishop added she planned to call her PNG government counterpart when she gets more details from Australia's representatives on the ground in Port Moresby.

Former Greens leader Bob Brown said Ms Bishop's initial response was "pathetic".

"Over pile of #PNG student bodies, @JulieBishopMP calls for 'restraint' on both sides. PATHETIC!" he tweeted on Wednesday.

Labor deputy leader Tanya Plibersek said it was a concerning development.

"Labor is extremely concerned by reports that university students have been shot during protests in Port Moresby," she tweeted.