A three-year-old refugee has allegedly been raped at an asylum centre in Norway's Stavanger, the country's third largest city.

Local police is investigating reports that the boy, whose nationality has not been disclosed, was sexually abused in the common area of Forus Akuttinnkvartering centre.

Authorities from the southwestern city were called to probe the incident on January 6 at around 10pm.

Local police is investigating reports that the three-year-old refugee, whose nationality has not been disclosed, was sexually abused in the common area of Forus Akuttinnkvartering centre (stock picture)

'We have no suspects yet,' police superintendent Bjørn Kåre Dahl told local newspaper Stavanger Aftenblad, as reported by The Local.

'We are investigating the case as if the worst thing has happened and that we are talking about the rape of a child'.

Dahl did not rule out that there could be several perpetrators. 'We will investigate further to find out what happened. If it is what we fear – a rape – then this is very serious. But we do not know for certain yet,' he said.

The boy, who has been taken to the rape crisis clinic with his mother and then to the children's ward at Stavanger University Hospital, has been questioned by authorities along with several other people.

'We also had crime technicians on the site. Material was sent to the Norwegian Institute of Public Health for analysis. There, they will look for DNA among other things,' he said.

'We had many people at work, both sanitation workers and security guards, but nobody saw anything. But we immediately took the case to the police, as is the routine, and they came out. We have had a good dialogue with them throughout,' he said.

The Forus centre hosts some 800 asylum-seekers.

A spokesman for the centre said they received a phone call about the incident but they did not see or hear anything.

The alleged incident took place after Norway announced it was offering non-European asylum-seekers classes in Western sexual norms, in an attempt to prevent violence against women.

Linda Hagen of Hero, a private company that runs 40 percent of Norway's reception centres for refugees, explained that the aim is to help asylum-seekers 'avoid mistakes as they discover Norwegian culture'.

'There's no single cultural code to say what is good or bad behaviour because we want a free society,' she said.

'There has to be tolerance for attitudes that may be seen as immoral by some traditional or religious norms.'

The courses were launched after a 'wave of rapes', committed mostly by foreigners, took place in Stavanger between 2009 and 2011.

The course, which Hero has tacked onto the immigration agency's broader, mandatory introduction programme to Norway, addresses the problem of sexual assault, using concrete examples for the participants to discuss.

'It could be an 18-year-old guy who says he's surprised by the interest some Norwegian girls are showing in him. He assumes they want to sleep with him,' Hagen said.