Updates will be provided when available, the police said in a statement.
The missing person at Waihī was part of a group at the beach, a police spokeswoman said. Residents understand he is a boy of about 17 from the Hamilton area.
Coastguard, surf lifesavers, and search and rescue teams were helping with the efforts.
Police described the sea conditions as rough and two local residents told the Bay of Plenty Times surf conditions were "quite gnarly".
A Waihī Beach Surf Lifesaving Club representative said lifeguards were in the water and "giving it their best effort".
Two Coastguard vessels were out searching yesterday, along with the Auckland Westpac Rescue Helicopter, which carried out grid searches in the area, she said.
Surf Life Saving NZ is urging beachgoers to be extra vigilant this weekend, and throughout the rest of summer following an increase in serious incidents.
National lifesaving manager Allan Mundy said lifeguards worked hard to keep people safe by patrolling beaches, and operating Search and Rescue squads that were activated after patrols went home.
Waihi Beach. Photo / File
Nobody was stronger than a rip and swimmers needed to help surf lifeguards help them, he said.
The message was simple: "Swim between the red and yellow flags and remember the 3Rs – relax and float, raise your hand and ride the rip."
Water Safety New Zealand chief executive Jonty Mills said the past 48 hours had been a tragic time for families and the country as a whole. In less than 48 hours, there have been drownings at Langs Beach and Baylys Beach in Northland and the Police Dive Squad located a body from the Whanganui River yesterday.
The hot summer was making it inviting for people to get in the water at beaches, rivers and lakes, but he warned water conditions could be unpredictable and changeable.
Mills said there had been 20 water fatalities this year, compared with 22 at the same time last year. The deaths were across a range of ages, activities and environments.
With a diverse population and visitors unfamiliar with New Zealand waters, it was important for people to swim between the flags, Mills said.
Lincoln Davies from the Auckland Rescue Helicopter Trust said crews were tasked by police to Waihī Beach about 1.15pm yesterday. He said they worked alongside coastguard and SLSNZ for two hours before being stood down.
They did not find anything in yesterday's search and had not been tasked to the scene today, he said.
