A search is underway for a person who was swimming at Waihi Beach this afternoon.

Police were advised that there was a person having trouble in the sea at 12.40pm today, says a police spokesperson.

"The person had been part of a group swimming at the beach."

An initial search was carried out by the Auckland Westpac Rescue Helicopter, however, it was unsuccessful.

"Waihi lifeguards, IRBs and the Coastguard are currently continuing with a search."