A group of Papua New Guineans has demonstrated outside the Australian High Commission in Port Moresby, calling for the choice to become Australian citizens.

Most want to stay in PNG but believe Australian citizenship may bring access to better health care and education.

Several hundred people waved Australian flags and sang the Australian national anthem in their local language.

Most were born before 1975 when PNG became independent from Australia.

Jonathan Baure from the Papuan Plaintiff Group says they want the choice to become Australian citizens.

"What the dispute is that when independence came, whether we lost that or not, we don't believe we lost it because we never renounced it," he said.

"That choice has to be given to us."

A representative from Australian High Commission told them the High Court of Australia has already rejected their claims.