Police have charged a teenager over the alleged gang rape of a 14-year-old girl who was walking home through a park in Sydney's west.

Officers say the 16-year-old boy presented himself to Blacktown Police Station on Thursday evening.

He has now been charged with sexual assault.

He has been refused bail and will face court on Friday.

The 14-year-old girl was walking through a park at Doonside on Saturday night when she was approached by a man who spoke to her before allegedly overpowering and sexually assaulting her.

She was then allegedly assaulted by five of the man's friends.

This week police launched an investigation searching for six men of African appearance in their late teens to early 20s.

The girl is of Pacific Islander background and police and community leaders have been working for the last few days to defuse any tensions between ethnic groups in the area.

The local police commander and members of the African and islander communities led a delegation through the heart of Blacktown on Thursday to assuage concerns.

"It's important to separate this issue, this horrendous crime, compared to a race issue," Superintendent Garry Merryweather said.

Joe Tau from the Islander community said the walk through Blacktown was about strengthening the community in the wake of the attack.

"Things happen in the community that I guess that puts the community at a halt sometimes," he said.

"It's just a matter of us getting together and acknowledging that our difference is what makes us strong as a community, pick up and move forward.

It is not clear if the attack was racially motivated, but lawyer Deng Thiak Adut from the Sudanese community is worried that innocent Africans around Blacktown could be unfairly targeted.

"I'm not trying to create a fear factor here, but if they're hanging around at night or after six then that's a big problem," he said.

"At this stage, people should think about how they walk."