Corruption and police abuse will only end in Papua New Guinea when officials are held accountable for their actions.

This was disclosed by the Human Rights Watch which accused the government of failing to protect victims on Friday.

Dozens of people were injured and one man killed in June after police in the Pacific nation fired at students protesting against Prime Minister Peter O'Neill over corruption allegations, which he denies.

"People took to the streets to voice concerns about corruption, and the only government response was gunfire," said Human Rights Watch's Australia director Elaine Pearson as the global group released its annual report.

"Corruption and abuse will only end when abusive officials are held responsible for their crimes."

Police brutality, including towards children, "continues with little accountability even for fatalities and egregious physical abuse", the report said.

Despite 1,600 complaints of police abuse between 2007-14, with 326 classified as criminal cases, the government has not revealed if any of the accused officers had been convicted, HRW said.

The report noted that the impoverished, crime-ridden country remains one of the world's most dangerous places to be a woman, with "no meaningful reduction in the alarming rates of family and gender-based violence".

A law meant to tackle such abuse was passed in 2013, but has yet to be implemented, with police rarely pursuing investigations or criminal charges, the rights group said.

"The government is failing miserably to protect women and girls from discrimination and family violence," Pearson added.

"There is still a dire lack of services for people who have suffered family violence."

PNG also came under scrutiny over reports of violence against refugees at an Australian asylum-seeker detention camp on Manus Island.

The camp is set to be shut after a PNG Supreme Court ruling last year declaring that holding people there was unconstitutional and illegal, but HRW said neither the Australian nor the Pacific nation's governments had taken significant steps to close it.