Beachgoers in Dunedin are being urged to know their limits before taking to the water after surf life-savers rescued nine people in less than a month.
Surf Life Saving New Zealand Otago-Southland club support officer Sam Clutterbuck said most rescues had been in non-patrolled areas, and some people were clearly not aware of what was safe.
"We advise people to swim between the flags but we're trying to advise them, if they're going outside those patrol areas, of the safe places to swim.
"Go when the waves are breaking, and don't swim in flat water because that means currents and rips are taking water back out to the sea.''
The problem was highlighted again last week, when an 18-year-old first-time diver became stuck on Bird Island, off Smaills Beach, after the waves became too strong for him and his friend to swim back to shore.
The pair had gone out at low tide but were unable to get back an hour later.
"Talking to one of the lifeguards, he said the young boy had trouble swimming and was quite scared to enter the water again.''
The St Clair Surf Life Saving Club had been the busiest in Dunedin during the holiday period, Mr Clutterbuck said.
It had responded to five rescues, seven first aid calls and one search during its weekday patrols between December 21 and yesterday.
First aid calls usually involved cuts and other minor injuries, often resulting from falling on rocks, he said.
Both searches were successful.
As well as not being aware of safe areas to swim, it seemed some people were not aware of the level of ability required to swim in difficult conditions, he said.
"There's always going to be problems in rough surf.
"Even for lifeguards, we practise to swim in the rip and it's always hard.''
People who did get caught should swim sideways with the rip before swimming back to land, Mr Clutterbuck said.
Boogie boards and other floatable devices were dangerous in rough surf, as they could be pulled out to sea quickly, he said.
Ten drownings occurred across New Zealand during the holiday period, six of them in non-patrolled areas.
Those contributed to the provisional 2015 drowning toll of 23, more than double the previous year's total of 11.
Surf Life Saving New Zealand national life-saving manager Allan Mundy said the figures were a reminder people needed to question their swimming ability before entering the surf.
"Knowing how to swim is not enough - you also need a good level of fitness to successfully get out of a rip and/or cope with big waves knocking you around.
"Unless you've been swimming distances regularly, then you can't consider yourself safe swimming in moderate to large seas, away from patrolled areas.
"Being in a rip means you have to be able to swim in deep water for an extended period of time and you also have to remember that a series of big waves can keep you pinned underwater for up to a minute.
"If you can't hold your breath that long, you should not be going into the surf in those conditions.''
Surf life-saving
Callouts Since December 21 (weekday patrols)
St Clair: 5 rescues, 7 first aid calls, 1 search (successful).
St Kilda: 4 rescues, 1 first aid call.
Warrington: 2 first aid calls, 1 search (successful).
Brighton: 4 first aid calls.
