Although the Labor Government has allowed more women and children to be housed in the community while their refugee claims are assessed, there are still about 800 minors among the more than 4700 people held in immigration detention.
Morris, who works at the Royal Darwin Hospital, said one-third of those children were suffering from depression, and he called for minors to be detained for no more than three days.
According to the hospital, 33 children under 16 were admitted last year from Darwin detention centres, some of them after harming themselves or attempting suicide. An average of two adults from the centres turn up at the emergency department daily.
The Darwin sitting coincided with news that 75 unaccompanied children are to be transferred this week from Christmas Island to a detention centre in Leonora, in the Western Australian goldfields.
Refugee activists have condemned the decision to move the boys, aged 14 to 17, to such a remote location, and one lacking mental health care facilities. The Leonora shire president, Jeff Carter, said the teenagers were welcome in the town, where they would attend the local school. But he said he was concerned about them being isolated.
"I just don't like the idea of juveniles being locked up," he told the Australian. "It's wrong. They haven't committed a crime, asking for refugee status in Australia. I just reckon the federal Government and all sides of politics really want to have a good look at themselves. This is just ridiculous, what they're doing."