A leader in Melbourne's South Sudanese community has accused key government figures of racial stereotyping and demanded an apology after recent comments about an apparent African youth crime problem.

South Sudan Australia Peace Initiative coordinator Nyok Gor wrote in an open letter to Prime Minister Malcolm Turnbull that the government had "stereotyped our whole community".

"Your claims about a 'youth crime wave' and (Minister for Home Affairs) Peter Dutton's comments about 'African gang violence' are factually inaccurate," he wrote.

"Victoria Police have repeatedly demonstrated reducing rates of youth crime and deny that there are any African 'gangs' in Victoria.

"You have a duty to use your position to benefit Australian society, not to perpetuate inaccurate and biased narratives that negatively impact on our community and our daily lives."

Related reading Melbourne could take lead from Sydney on youth crime problem, Sudanese refugee says

Mr Gor said such stereotyping "perpetuates youth marginalisation and affects our capacity to gain employment and integrate more fully".

The letter comes after Mr Dutton claimed last week Melbourne residents were "scared to go out at restaurants" at night due "African gang violence".

He told radio station 2GB Melburnians were worried of being "followed home by these gangs" and falling victim to "home invasions and car (thefts)".

"There's no deterrence there at the moment ... People don't see this in New South Wales, in Queensland," he said.

Mr Dutton later told radio station 3AW he had come to this conclusion after speaking to a "number of people".

Prime Minister Malcolm Turnbull similarly cited the problem – expressing concern about "the growing gang violence and lawlessness in Victoria".

Mr Gor has joined growing criticism against the government for these statements.

Centre For Multicultural Youth chief executive officer Carmel Guerra told SBS News the "media hysteria" around this issue was having adverse effects among African-Australian young people.

"I'm concerned that these comments paint all young people from this community with the same brush," Ms Guerra said.

"I've heard that young (African-Australian) people are getting accused of being gang members when they've been walking the streets over the past few days."

Ms Guerra said "knee-jerk" comments like this should be avoided by politicians in the future.

Acting Victorian Premier Tim Pallas was also critical, saying Mr Dutton had "gone too far just to make a political point".