Nearly 1000 staff at the Royal Children's Hospital have rallied together and are refusing to discharge sick children back to detention centres over serious concerns for their welfare.

Doctors, nurses and clinical support staff gathered in solidarity at the Melbourne hospital on Saturday to send a message to the Federal Government that holding children in detention is 'harmful' and 'unsafe.'

'We see a whole range of physical, mental, emotional and social disturbances that are really severe and we have no hope of improving these things when we have to discharge our patients back into detention,' one doctor told The Herald Sun.

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The Royal Children's Hospital has refused to return sick children to detention centres

'Detention causes harm and it must end. Children in detention have nightmares, bed-wetting, and behaviour problems,' another said.

Earlier this year, the Federal Parliament passed two laws that threatened two years' jail for any health worker who spoke out against conditions in detention centres.

Despite this, hordes of staff congregated out the front of the emergency department, punching their fists in the air and holding a sign that read, 'Detention Harms Children.'

Immigration Minister Peter Dutton responded to the rally and said that he continues to support the current government policy on children in detention.

Around 100 children are currently residing in immigration detention centres across Australia

'I understand the concern of doctors, but the Defence and Border Force staff on our vessels who were pulling dead kids out of the water don't want the boats to restart,' Mr Dutton said.

The chairman of The Royal Children's Hospital Rob Knowles continued to support his staff and their right to share an opinion on the issue.

Around 100 children are currently residing in immigration detention centres across Australia.