Save the Children Australia says it has no reason to believe any of its staff acted inappropirately after its offices on Nauru were raided by police.
The offices were raided on Saturday afternoon, and Nauru police reportedly seized computers, mobile phones and other devices including flash drives.
The Guardian reports that the raid was an attempt to hunt down journalists' sources at the Australia-run asylum seeker detention centre on the island.
Australia's immigration department says it had nothing to do with the raids.
In a statement, Save the Children says it has not reason believe that any of its staff have acted inappropriately, but the organisation is assiting Nauru police with their inquiries.
Last year, nine Save the Children staff were deported from Nauru after they were accused of encouraging detainess to self-harm and make up stories of abuse.
They were later cleared by a government inquiry.
Australia's Greens say a raid of Save the Children's office in Nauru is designed to intimidate people who may speak out.
Its immigration spokesperson Sarah Hanson-Young says the raid is very concerning.
"This is all about intimidation. It is heavy handed and it is more of the activities of cowboys than it is of appropriate, responsible government."