Brightly-coloured red and orange Chinese lanterns are being  mistaken for distress flares,  sparking search-and-rescue operations off Northland's coast.
In January police launched six night-time searches after people believed they had seen a flare indicating a marine emergency.
The objects were actually lantern-type fliers powered by small candles. They have also been responsible for starting  at least one fire.
Northland Police Search and Rescue acting co-ordinator Detective Kelly Penney urged people who wanted to release the coloured paper lanterns not to use red or orange ones.
"These glowing red fireballs are being regularly mistaken by members of the public as flares. They can be spotted up to two kilometres out to sea," Mr Penney said.
"Valuable resources are often deployed to investigate the sightings."
Mr Penney said while police did not want to deter callers for fear of missing a genuine call for help, they wanted people to be aware of the difference.
Mr Penney said a red marine parachute flare was known internationally as a distress signal.
When released there was a distinctive bright initial red flash. The flares reached a height of up to 300m before a parachute was activated for  a slow descent.
"The Chinese lanterns stay in the air for several minutes, display a red or orange glow, will not be quite as bright as distress flares and drop fairly rapidly," Mr Penney said.
The lanterns have sparked callouts at Matapouri, Whangarei Harbour, Taiharuru, Pataua South and Waipu. One lantern spotted by  boaties near Ruakaka blew onshore and sparked a scrub fire.