Rough conditions caused a boat to capsize on the Kaituna River bar, plunging the two occupants into icy water.

They managed to swim to shore, where they were attended to by an ambulance yesterday.

Maketu Coastguard president Shane Beech is warning people to be prepared before they head out onto the water.

Conditions at the bar were miserable, say locals, with a gale warning in force, winds around 25 knots and a swell peaking at 4 metres.

The Kaituna River was swollen due to heavy rain in the region.

Maketu Coastguard president Shane Beech was among those who responded to the incident at about 4pm.

'Two guys went out in a five-metre aluminium boat. They were crossing at the Kaituna River bar, heading out to set a net, when a wave capsized them.

'They were caught under the boat, in part of the net, but managed to free themselves. They them swam to shore and ended up roughly 400 metres on the Papamoa side of the Kaituna cut, on the beach.”

The Maketu Coastguard launched their rescue boat and managed to locate the pair, bringing them to a waiting ambulance.

'One of them was extremely cold, shaking, hypothermic, with a few bruises. The other one wasn't as bad: he was alert and talking to us.”

In light of the incident, Shane's advice to boaties is to be prepared.

'Basically, look at the weather conditions. The seas were extremely rough; the bar was pretty well unworkable. And of course, wearing life jackets is always part of the advice we give.”

Maketu Coastguard's Eastpack Rescue, in better weather. File Photo.