Federal police have been called to the scene of a rooftop protest at Villawood detention centre.
Three people have been protesting from a roof, estimated to be at least 7 metres from the ground, for three days.
It is understood the three are Fijian nationals, and their protest was sparked when a woman scheduled to be deported on Monday climbed on to the roof on Monday.
Her husband was also due to be deported on Tuesday, but he remains at the centre after the woman threatened to jump from the roof if he was removed.
A spokesman for Immigration Minister Chris Bowen said Australian Federal Police were on site, but could not say whether there were police negotiators are the centre. He said employing police negotiators to try to bring the trio down was an operational matter.
Serco, the company running Villawood for the government, had trained negotiators talking to the group, he said.
Serco had also placed crash mats on the ground below the roof.
An AFP spokesman said federal police would support the department and Serco to safely resolve the situation.
''As this is an ongoing incident, it is not appropriate for the AFP to comment further.''
NSW police confirmed local police had not attended the scene, despite receiving a call on Tuesday.
A department of immigration and citizenship spokesman said: ''We won't be discussing the specifics of what's happening on the ground.''
Lawyer George Newhouse, who acted on behalf of the family of 36-year-old Fijian national Josefa Rauluni, who leapt to his death in 2010, was visiting clients on Monday and witnessed the protest.
By Tuesday night friends of the trio were sending him text messages pleading for help.
''George, please I am very scared that they might jump please help them.thank you,'' read one.
The story Federal police called to rooftop protest at Villawood first appeared on The Sydney Morning Herald.