Hundreds of people marched to the Australian parliament on Tuesday to demand the government suspend its policy of sending asylum seekers and refugees to remote Pacific territories, and bring children already detained on Manus Island to Australia.

About 500 protesters representing 30 different groups from around rural Australia, including high school students, took part in the rally, amid mounting concern over a five-year-old offshore detention policy that requires any asylum seekers who attempt to get to Australia by boat to be held offshore and banned from ever settling in Australia itself.

The march was organised to “focus attention on the plight of asylum seekers and refugees who remain on Nauru and Manus Island, and particularly the need to provide homes and safety for children and their families either in Australia, or in another country that would welcome them”, Rural Australians for Refugees said in a statement.

On Monday, nearly 6,000 doctors delivered a letter calling on Prime Minister Scott Morrison to remove children from detention given the serious physical and mental health risks they face.

“The medical profession is demanding children and families be moved from Nauru,” the Australian Medical Association tweeted on Tuesday. “For thousands of doctors to be motivated to take this course of action is testament to the severity and the urgency of this issue.”

Three representatives from the ruling Liberal Party also broke ranks to call for the children to be brought to Australia.

About 1,100 people are currently being held on Nauru including 102 children, according to the Asylum Seeker Resource Centre. Single men are detained on nearby Manus Island.

Looming by-election

The fate of the families threatens to become a major political problem for Morrison’s government, which has a parliamentary majority of just a single seat and is facing a by-election this weekend in Sydney.

The constituency of Wentworth, which includes the beachfront suburb Bondi and some of the city’s wealthiest neighbourhoods, was previously held by Malcolm Turnbull who was deposed by Morrison in late August.

“The issue is front and centre of the by-election campaign,” said Al Jazeera correspondent Andrew Thomas.

In a close race, the Liberal Party is defending a winning margin of 17.7 percent, which was supported by Turnbull’s personal popularity. The electorate is seen as one of the most progressive in Sydney.

Doctors Without Borders (known by its French initials, MSF), which worked on Nauru for nearly a year until it was forced to leave by the island’s government last week, said the mental health situation was “beyond desperate”. The medical group was given just 24 hours to leave.

“The mental health situation of the refugees indefinitely held on Nauru is devastating,” Dr Beth O’Connor, MSF psychiatrist, said in a statement last week. “Over the past 11 months on Nauru, I have seen an alarming number of suicide attempts and incidents of self-harm among the refugee and asylum-seeker men, women and children we treat.”

Some children were suffering from traumatic withdrawal syndrome and were unable to eat, drink or even walk to the toilet, O’Connor added.

The United Nations High Commissioner for Refugees has also called for the evacuation of the offshore camps given the deteriorating health of those confined there, stressing that Australia has a responsibility to those that seek its protection.

‘OK to be white’

Meanwhile, Morrison’s government is also facing ridicule after some of its own members backed a parliamentary motion declaring “it is OK to be white”.

Officials blamed an “administrative process failure” after it emerged on Tuesday that the attorney general had issued instructions to Liberal members to back the motion, drafted by right-wing populist Pauline Hanson and railing against what it described as “the deplorable rise of anti-white racism”.

The motion was defeated 31-28, with several government ministers voting in favour, including its top official for indigenous affairs.