They warned New Year festival-goers on their way to Gisborne to expect heavy traffic and to drive sensibly.
The annual Rhythm and Vines festival starts today at Waiohika on the outskirts of Gisborne, while its sister festival BW began in Gisborne city on Saturday.
Thousands of young people from around the country have been streaming into the city and police say traffic hold-ups are to be expected.
"These two festivals bring around 20,000 extra people into Tairawhiti and that means lots of bodies and lots of cars," Tairawhiti Area Commander Inspector Sam Aberahama said.
"So we ask that everyone drives sensibly - which means don't speed, be patient and if you feel tired, pull over and have a rest."