Coastguard Queenstown is collecting old flares from boat owners to dispose of them safely, part of a South Island-wide collection.
Coastguard southern region manager Cheryl Moffat said out-of-date or time-expired flares could be dangerous and should not be used.
Given flares were ''pyrotechnic devices'', they should not be burnt or put into the rubbish.
If they ignited they could cause fires, while parachute flares fired horizontally could cause potentially fatal injuries or burns.
''Definitely don't throw them overboard, as flares will cause pollution,'' Ms Moffat said.
If boat users were in doubt about the expiry date of flares, or if the flares had ''seen better days'' they should consider disposing of them, Ms Moffat said.
''When you need to use them, you want to be sure that they will work.''
Flares were one of three communication devices Coastguard urged boat users, kayakers and other water users to take with them - a VHF radio and cellphone in a waterproof bag were also recommended.
Residents in the Queenstown-Lakes district can contact Coastguard Queenstown's Andy Tucker on 021-234-9768 to arrange for old flares to be dropped off by August 16.
