Hunters are being urged to following firearms safety rules when the duck shooting season opens on Saturday after the recent gun-related deaths of two deer hunters.

The Mountain Safety Council and Fish & Game NZ are both appealing to game bird shooters to adopt a safety first approach.

"I encourage all those hunters heading out on Saturday morning to take a few minutes to refresh themselves with the seven golden rules of firearms safety," said Fish & Game NZ chief executive Bryce Johnson.

Johnson says hides can pose a unique problem for duck shooters.

"One of the greatest dangers in duck hunting is unsafe handling of firearms in the maimai - hunters need to be particularly careful when they have loaded shotguns in confined spaces with others present," he said.

Last season a Waiuku man was shot dead on the opening day of the season.

MSC firearms safety manager Mike Spray says each season there are reports of incidents involving the careless use of shotguns and he urged shooters to take steps to ensure they stayed safe, including ensuring they got enough rest.

"Late nights and early mornings can compromise safety and tired shooters are likely to be less alert and may be more likely to drop their guard," he said.

Two hunters were shot dead in April after being mistaken for deer by fellow hunters.

Southern district police will be conducting an operation on hunters this weekend with a focus on the dangers of mixing firearms and alcohol.

"It is essential to keep firearms and alcohol completely separate," Inspector Al Dickie said.

Meanwhile, hunters in Canterbury are being told to steer clear of two lakes which have toxic algae.

The Canterbury District Health Board says Lake Ellesmere and Lake Rotorua near Kaikoura have algae blooms above levels considered to be safe for recreational activities.