The Mangawhai Heads Surf Club building was heavily damaged after heavy rain caused a massive slip on the hillside behind the clubhouse.

The club’s public relations officer Tony Baker said hundreds of tonnes of rocks came down the hill around midday on Wednesday.

“It completely took out the female toilets, half the men’s toilets and the internal staircase…The photos actually don’t do it justice, they don’t really show the scale of it.”

Professional lifeguards were on duty and inside the building at the time, Baker said, but no one was seriously injured. The clubhouse was quickly evacuated.

“We had a couple of our senior members on the property at the time – they just made a very quick decision, let’s just get the main rescue assets out.”

The building and its grounds have been cordoned off and were unable to be accessed, with the potential for more debris to fall.

The future of the building is unclear, Baker said, although it had not been written off yet.

“A lot of people have grown up around the place, from nippers right through to senior lifeguards and a lot of people are quite sad. It’s a very sad thing to have happen but we’re very grateful that no one was seriously injured.

“It’s been there for 60 years without incident, it was just a crazy weather event.”

Baker said the lifeguard service – although unable to operate on Thursday morning – would be able to continue despite the hopefully temporary loss of the building.

“The building might be fine, although it’s not fine at the moment, it’s pretty badly damaged.”

They would know more about the building’s future after meetings planned with Kaipara District Council and engineers, he said.

“We’ve got IRBs, we’ve got our vehicles, we’ve got gazebos and all of the lifesaving equipment,” he added.

There were items club members wanted to recover from the building if and when access was possible, Baker said.

“There’s a lot of memorabilia in the club – we obviously want to get that out of there.”

Lifeguards returned to the beach Thursday afternoon, Surf Life Saving Northern Region chief executive Matt Williams confirmed, and would be on duty over the weekend.

The beach remained accessible to the public, although Williams earlier urged people to stay away from the beach while patrols were not operating.

No access is currently possible to the grounds around the club, as the land is still unstable.

Although all urban beaches in Auckland are currently “black-flagged” due to wastewater contamination and no patrols are operating, all Northland beaches remain open and lifeguards are on duty.