More than 600 asylum seekers and refugees are refusing to leave the Manus Island immigration detention centre, which is due to close next week.

Authorities will cut off access to drinking water, food, medical treatment, electricity and sewerage from next Tuesday.

Refugees will be forced to move to alternative accommodation centres nearer Manus’s main city of Lorengau. Services will be provided to refugees while they wait for resettlement elsewhere in Papua New Guinea or in a third country.

There are also 156 people on Manus whose bid for asylum has been rejected. They will be moved to a third accommodation centre, but are being encouraged to return home.

Senate estimates heard on Monday that 606 people who were required to leave by the closure deadline were refusing to move out.

Asked if they would be removed by force, the immigration department secretary, Michael Pezzullo, said that was a matter for the Papua New Guinean government. Pezzullo suggested the ordinary laws of trespass might apply because PNG was planning to reoccupy the former military facility.

“They don’t have a human right to trespass on a naval base,” he told senators.

Rohingyan refugee Imran Mohammad Fazal Hoque told the Guardian men were fearful of being abandoned in the Manus community, where low-level wariness has escalated in recent months to outright hostility.

“We have experienced riot, been shot at, assaulted, treated sometimes worse than animals, robbed and on many occasions beaten in front of the Australian security guards,” Hoque said. “We call for help in the vain hope that someone might answer. The fear that has grown in the inmates’ minds will never go away.”

Pezzullo rejected claims people were too scared to leave the centre, saying refugees could now come and go at will.

PNG’s security forces have a troubled history at the detention centre. In 2014, police officers were part of a mob that stormed the centre and attacked those inside during three days of rioting in which one asylum seeker was murdered and more than 70 seriously injured, including being shot, having their throats cut and beaten with wooden staves.

In April this year, “drunken soldiers”, according to the police, shot at refugees and tried to ram a vehicle through the centre’s gates.

The centre is closing because the PNG supreme court ruled in April 2016 that the detention of refugees and asylum seekers was “illegal and unconstitutional”.

In June, the Australian government settled a court action to pay $70m in damages for holding men unlawfully, in dangerous and damaging conditions.

Australia retains effective control of the processing centre. All Australian government staff will leave the centre at the closure date, but the government will continue to have oversight. The government is in negotiation with a number of service providers to continue to support those held on the island.

Australia will spend between $150m and $250m supporting refugees and asylum seekers on Manus Island in the year after the regional processing centre closes.

Almost all the men held on Manus have been there more than four years. More than 71% have been found to be refugees – they have a “well-founded fear of persecution in their home country”, they cannot be returned home and are legally owed protection.

The government has offered refugees on Manus the chance to move to Nauru while they await possible resettlement in the US. Two refugees have expressed an interest in going.