PM questions reason for Vic gang problem

Scott Morrison has questioned why African gang violence is a problem in Melbourne, saying it doesn't happen in Sydney because NSW has a "police force that's a force".

The ongoing gang violence in Melbourne has sparked debate between the Victorian and federal governments about the extent of the issue and its causes.

The Sydney-based prime minister says the city has a law and order problem not witnessed in Australia's other major cities.

"We have (Australia's) highest proportion of Sudanese population in NSW," Mr Morrison told 3AW on Monday.

"We don't have these problems in NSW, they're not happening in other cities. Why is it happening in Melbourne?"

The prime minister recounted how former NSW Police Commissioner Andrew Scipione changed the name of the NSW Police Service to NSW Police Force, bringing about a cultural change.

"Law and order means something in NSW and I feel for Victorians who are asking the big question, why is this happening in our city and it's not happening in other places," he said.

"There's not the same issue, even though we have the same challenges in other cities in the country, including in my home city of Sydney, because we have a police force that's a force."

He said it was up to Victorian Premier Daniel Andrews to ensure "there is a police force that is a force".

"When you don't have that control and rule of law being imposed and forced in your community, people take advantage of it," he said.