It was a busy day for lifeguards at beaches all around the country on Sunday, with nine swimmers at Auckland's Bethells Beach needing to be treated for blue bottle stings.

Surf Life Saving New Zealand Chief Operations Officer Chris Emmett says staff made 22 rescues at the weekend - 18 of them on Sunday.

It helped with a further 44 assists - all but two of them were on Sunday.

Pāpāmoa lifeguards in the Bay of Plenty had to assist 20 people back to shore throughout the day as strong currents troubled many swimmers.

In Waihi, two people were plucked from a rip using an inflatable rescue boat.

Warm, sunny weather on Sunday saw huge numbers of swimmers flock to the beaches - and causing some headaches for lifeguards.

Omaha Beach saw 1400 people on the beach in the afternoon - the highest in the northern region.

Mount Maunganui had the busiest day in Surf Lifesaving's eastern region with 1300 beach users at one point.

Taylors Mistake in Christchurch was the busiest beach in the south.

Beachgoers had been well-behaved, Chris says.

But lifeguards had been pressed dealing with a large number of swimmers making the most of the sun before heading back to work.

RNZ