The sister of the teenage victim desperately called for calm on Wednesday after friends encouraged her family to "go out there and fight".

The victim, who is of Pacific islander background, told police she was assaulted by six men of African appearance in a Doonside park on Saturday night.

Two friends of the victim had vowed on social media to stab and kill Africans in Doonside.

The victim's sister responded by saying "what we need is peace especially my parents and ... my baby sister".

"Please stop whatever negativity you have to say to my siblings about beating up gang bashing, jumping, dog shots whatevz [sic]," she posted online.

"Let my family deal with what needs to be done to help our baby sister get through this."

Sudanese lawyer and respected community figure Deng Thiak Adut said he had spent each night this week at Blacktown station trying to quell tensions between groups of young African and islander men.

He met with Blacktown police to express concern over the vague description released of the six offenders as of "African appearance and ... aged in their late teens or early 20s".

Despite the plea, police were unable to provide any further detail on Wednesday, saying that was the only description given by the highly traumatised victim.

"Will there be any racial violence? I would say yes because of what is being reported," Mr Adut said. "There will be tension, there will be fights and some of these kids will enjoy it."

Blacktown Commander Superintendent Gary Merryweather said the victim was walking home through Bill Colbourne Reserve at 11pm on Saturday when she was approached by a man who sexually assaulted her.

He pinned her to the footpath where she was assaulted by another five men over 30 minutes.

Other sources have told Fairfax Media she was drinking in the park with the group.

Father Chris Riley, from Youth off the Streets, said he was mobilising "strike force" teams of African social workers to be deployed in Doonside and Blacktown in the next two weeks.

They will act as a quasi-police force, rushing to scenes of racial tension or sexual assault within five to 10 minutes.

"Where there's trouble in communities, we need to move in quickly," he said. "There is a locked-out underclass of young people in this area."

Almost 30 per cent of Blacktown's residents are aged under 19 and the area is home to 200 different ethnic and religious groups.

Pastor Ramese Tupe from, Doonside's Mountain View Seventh-Day Adventist, which has a predominantly Pacific islander congregation, said boredom was the biggest problem.

He planned to talk to the youth congregation on Friday night to urge them to be calm.

"The young men get bored easily so we're trying to work with them to find a sense of belonging with the church and their family," he said.

Superintendent Merryweather said he had spoken with many community members and they were "calm and very committed to ensuring that their good work is not blemished by speculation".

Officers investigating the rape continued to speak to witnesses, local business owners and residents on Wednesday.