Invercargill police have called in reinforcements to patrol city streets after reports rival gang members are heading south.
"We have had a lot of reports of gang members heading this way," Detective Senior Sergeant Brian Cowie said.
More than 30 gang members were spotted boarding a ferry for the South Island earlier this week.
They were believed to be headed to Invercargill but had not arrived by last night, he said.
Police in other centres were on "high alert" for gang members heading south.
For the second weekend in a row, eight officers from Dunedin had been sent south to boost police numbers in Invercargill.
Police would have a visible presence on city streets this weekend, with officers monitoring entrances to the city, he said.
"Everyone has the right to freedom, to move about, but if they are coming here with the purpose of committing crime, we will be dealing with them in the appropriate manner."
The armed offenders squad was on alert, he said.
"We are keeping a high profile and talking with the gangs."
The public was advised to go about normal business, but should report any suspicious activities to police as soon as possible, he said.
Police yesterday arrested four Mongrel Mob members - two from Christchurch and one each from Dunedin and Invercargill.
They appeared in the Invercargill District Court on driving, obstruction and liquor charges.
The Balmoral Dr headquarters of the Road Knights gang was last week destroyed by fire and police were treating the incident as arson, Det Snr Sgt Cowie said.
A property near the Mongrel Mob headquarters in Severn St was destroyed by fire last Saturday night.
A police team is investigating the incidents.
Charges have yet to be laid.
