A group of Christian protesters occupied the Sydney offices of Australian Prime Minister Malcolm Turnbull earlier today, demanding an end to the long-term detention of asylum seekers in centres in the South Pacific.

Around 20 activists, some holding a banner declaring "Children don't belong in detention", called on Turnbull to end the controversial offshore detention policy.

"I'm hopeful that we will look back at this particular moment, the change in prime minister, the fresh approach, and see that it was the time when that national shame was put to and end," said protest spokesman Justin Whelan.

Turnbull, who ousted former Prime Minister Tony Abbott in a party coup last month, was not in his office at the time of the protest.

Pressure is mounting on Turnbull to act on the harsh detention conditions, after reports of systemic child abuse and sexual assault and criticism by the United Nations and human rights groups.

Turnbull said last month he was concerned about conditions in the camps, but many in his Liberal party support the mandatory detention policy which has been a vote winner.

Australia's highest court is considering whether the policy of sending asylum seekers to the South Pacific island nation of Nauru for long-term detention is in breach of the constitution.

Australia receives nowhere near the number of refugees currently flooding into Europe, yet successive governments have vowed to stop asylum seekers reaching the mainland, turning boats back and sending those intercepted to camps on Manus island in Papua New Guinea and Nauru.

On Tuesday Nauru's Australian public relations firm, Mercer PR, caused outrage after releasing the name of an alleged rape victim after she had spoken to the Australian Broadcasting Corporation under the condition of anonymity.

That followed a raid on Saturday of the local offices of Save the Children, which works with detainees at the camps, in which laptops and mobile phones were seized by police.

Save the Children spokeswoman Olivia Zinzan defended the integrity of her staff and organisation, which has not had its contract renewed following clashes with the Abbott government over conditions at the facilities.

"As always, our priority remains working to mitigate the harmful impacts of offshore immigration detention, to the extent that the circumstances allow," Zinzan said.

Nauru has made it virtually impossible for journalists to visit by imposing a non-refundable A$8,000 (£3,800) visa application fee which few media outlets are prepared to pay.

Al Jazeera English said on Wednesday that despite having offered to pay the non-refundable fee, it had been told all media had been barred from the country. Nauru said the media outlet did not "go through the proper channels" to apply for a visa. Al Jazeera English disputed that in a statement.