Surf lifesavers are urging Aucklanders to be safe in the water, following four rescues and two people losing their lives in one day

Two people in their 20s died in incidents at Lake Wainamu and Karioitahi Beach on Monday night.

Surf Life Saving Northern Operations Manager James Lea says Monday's conditions created a perfect storm of conditions that put swimmers at risk.

He says the hot weather's attracting more people to beaches after lifeguard patrols have closed, and there's also been large surf.

Lea warns west coast beaches are particularly dangerous at low tide with stronger rips.