JET SKI riders and people sailing boats with engines are being warned they have been banned from two sections of Lake Eppalock under an "urgent" safety rule issued by Maritime Safety Victoria.
The water craft were barred from areas of Randells Cove and Strath Cove until further notice on Christmas Eve under the swift rule change.
Lake manager Goulburn Murray Water is issuing a warning of its own as crowds of holiday makers descend over the New Year's break.
GMW has put up signs and is urging people to avoid the areas for the safety of others, storage manager Paul Wakenshaw said.
"The safety of all visitors to our storages is our number one priority, so please follow the advice and ensure these areas are only used for bathers and manually operated craft," he said.
People who breach the rules could be fined up to $3305.
GMW has also reminded people to comply with COVID-safe guidelines amid a pandemic that by New Year's Eve had reappeared in Melbourne following a lengthy absence.
"Most importantly, people must give each other space, carry a mask and practice good hygiene. We hope these basic rules allow all visitors to continue enjoying our storages throughout the COVIDSafe summer, Mr Wakenshaw said.
Authorities are urging travellers to get tested if they show any sign of symptoms and have issued new statewide restrictions as contact tracers try to control a potential outbreak in multiple locations around the state.
They have also announced a complete border closure with New South Wales in coming days.