UPDATE 3.30PM: Police have confirmed one person "was unable to be revived" following a water rescue operation off the coast of the Coromandel.

"Six people have been pulled from the water."

The police spokesperson says one person is in critical condition, and the other four are in minor-to-moderate conditions after being rescued at Opoutere Beach, north of Whangamatā.

A search is still ongoing for a missing swimmer in the area.

"Emergency services were alerted by individuals who saw a group of seven people signalling for help, at about 11.25am today."

The search for the missing person will be assisted by a fixed-wing aircraft later this afternoon.

EARLIER 3.16PM: According to a post to the Coromandel's CFM Facebook page, one person is deceased following a water incident off the coast of the Coromandel.

The status of those involved has not been officially confirmed by authorities.

"One person is deceased, one person is missing and one person is in critical condition," the post reads.

"Numerous support people are in attendance including three rescue helicopters."

EARLIER 1.18PM: A person is missing in the water off the coast of Coromandel, Surf Lifesaving says.

At least one person is in a critical condition after a number of people got into difficulty at Opoutere Beach.

A Surf Lifesaving spokesperson says "several" others are being treated on the beach.

Police say emergency services responded to a serious incident at the beach, north of Whangamatā, about 11.30am.

Two Westpac rescue helicopters are at the scene.

A St John spokesperson said they received a call at 11.27am on Wednesday.

Three helicopters, three ambulances and two managers responded to the scene and treated seven patients.

One person is in a critical condition and has been airlifted to Waikato Hospital, while another person in a moderate condition is being transported by road to Thames Hospital.

Three other people suffered minor injuries.

The Westpac Auckland Rescue helicopter was among the helicopters that attended and flight radar shows it flew what appears to be a search pattern along the beach but did not land.

Opoutere is about 11kms north of Whangamatā and is sparsely settled but has a camping ground.

A local resident says that it's a terrible swimming beach and does not have lifesavers on it.

'And with the weather we've had recently it's pretty rough. Whangamatā has had similar conditions, and they had closed their beach with the recent weather.”

MetService says in its marine forecast for Coromandel today that winds could reach 25 knots, gusting to 35 knots in the afternoon.

It expects the sea to become "rough for a time in the afternoon and early evening".

"Cloud increasing, then fair visibility in isolated showers from afternoon. Easterly swell 2 metres, rising to 2.5 metres this afternoon."

-RNZ. and Stuff.

EARLIER:

At least one person is reported to be in critical condition afte a serious water incident in the Coromandel.

Emergency services are responding to a serious water incident at Opoutere Beach, north of Whangamatā.

"Police received a report that a number of people were in difficulty in the water about 11.30am," says a police spokesperson.

"At least one person is reported to be in a critical condition.

"More information will be provided when it becomes available."

A caller to the 0800 SUNLIVE news hotline says they were travelling down from Whitianga back to Tauranga and passed multiple emergency services heading towards Whangamatā.

SunLive is working on gathering more information and will provide an update as soon as possible.