Police reinforcements are being brought into the Hawke's Bay town of Wairoa for the tangi of three Mongrel Mob members who died after a car crash.
Officers would be monitoring the event and would respond to any trouble, they said.
Meanwhile, detectives said the 'rumour mill' about gang retribution in Hawke's Bay was 'working overtime'.
Police are calling for calm over talk of trouble, as they continue to investigate whether the members' car was run off the road before being found in the Mohaka River.
Officers said claims had been made in mainstream and social media that gang retribution was imminent and retaliation expected from rival gangs.
They had not received any reports of gang clashes or altercations - and any rumours have no basis or truth to them, they said.