A Serco guard at a Melbourne immigration centre has been sacked following allegations he made inappropriate sexual advances towards a female detainee and sexually harassed female guards while on duty.

Key points: The alleged harassment was reported to Victoria Police

The alleged harassment was reported to Victoria Police 13 allegations of sexual harassment were made against the guard by other staff

13 allegations of sexual harassment were made against the guard by other staff An internal Serco probe resulted in the sacking of the guard

The male guard was initially stood down in mid-December after a female Iranian detainee made allegations he had ushered her into an office, encouraged her to sit on his lap and then kissed her on the cheek at the Melbourne Immigration Transit Accommodation (MITA) centre in Melbourne's north.

On a separate occasion the guard is alleged to have sat on the woman's bed and rubbed her thigh.

The woman detailed the alleged harassment in a statement to Victoria Police.

"[He] came into my room, I didn't see him come in because my head was down and I was upset," the woman said in her statement to police.

"He said to me 'stop crying' and sat down beside me on my bed. He sat on my right and when I looked up I saw it was him and I moved away from him and I said 'What are you doing here?

"He said, 'How are you honey?' and he put his hand on my thigh and started to rub my leg with his fingers."

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'I thought he was drunk'

The woman also claimed the guard had been drinking alcohol while working on night shift, and rubbed the pregnant belly of another detainee.

"I could smell on [the guard's] breath alcohol and I thought he was drunk. That is what I was uncomfortable about, I felt he was dangerous because he was drunk," she said.

The woman disclosed the alleged harassment to a mental health nurse at the immigration centre and two days later Victoria Police took a statement from her.

A Victoria Police spokesperson said the matter had been referred to the Australian Federal Police (AFP) because the alleged incident occurred in immigration detention.

In a statement, the AFP said that it was not proceeding with an investigation into the guard.

"The AFP assessed the information and evidence provided in the referral and deemed that no Commonwealth offences were disclosed," the spokesperson said.

"The AFP considers this matter finalised and therefore it is not appropriate for the AFP to comment further."

The woman's lawyer Daniel Webb said his client had been anxious about making the complaint about the guard's behaviour and was anxious about her ongoing detention.

"The system comes down on [detainees] like a tonne of bricks if ever they get upset and are suspected of doing the slightest thing wrong," Mr Webb said.

"We must apply the strictest of standards to those who are working in position of power over such vulnerable people," he said.

Female guards raise further sexual harassment allegations

During an internal investigation following the allegations, a number of female guards working at MITA complained that they had also been sexually harassed by the same guard while on duty with him.

The ABC understands 13 allegations of sexual harassment were made against the guard by other staff at MITA.

In a statement, a Serco spokesperson said the company offered round-the-clock support to its employees.

"Serco became aware of further allegations of inappropriate behaviour against staff as part of the investigation into original claim and take these allegations very seriously," the spokesperson said.

The internal investigation has been concluded and the guard was sacked late last month.

A spokesperson for the Department of Immigration and Border Protection confirmed that an officer had been immediately stood down from duty and the alleged victim had been provided with medical support.

"The department takes allegations of inappropriate conduct very seriously," the spokesperson said.

"Any allegations of inappropriate behaviour by service provider or departmental staff at detention facilities are immediately reported to the department for investigation, as is the case in this instance."