Thirteen more refugees detained in Papua New Guinea by Australia have been returned to Manus Island from Port Moresby.

Photo: supplied

They were flown back on Thursday by the PNG immigration authority after spending months in a motel receiving medical treatment.

Some of the men's health issues had not been resolved, a refugee still in the motel said.

The 13 flew out after another group of 13 men were returned to the island on Thursday, who had unsuccessfully tried to resettle in PNG.

Earlier this month, about a dozen men were returned to Manus from the motel, who were also said to have unresolved health problems.

Meanwhile, a refugee on the island attempted suicide on Thursday, according to the journalist and Manus Island refugee Behrouz Boochani.

Another refugee on Manus was taken to hospital by police on the same day after attempting self harm, Mr Boochani said.

He said the men urgently needed psychiatric care not available on the island.