Beaches from Mount Maunganui to Papamoa are closed for swimming due to large swells and the threat of containers and debris from the grounded cargo ship Rena.

Maritime New Zealand is reporting more containers have fallen from the Rena during the storm overnight, and are being sighting northwest of the Astrolabe Reef, where the ship grounded.

A surf lifeguard puts up a sign closing Mount Maunganui beach to swimmers.

Omanu surf lifesaver Thomas Yule, 22, says the threat of debris and containers in the water, along with swells of up to 7ft are making sea conditions along Western Bay of Plenty coast dangerous.

'We closed the beach to swimmers as it is too dangerous with the storm and the containers off the Rena.

'At the moment we are trying to keep people out of the water, at all times, including ourselves.”

Standing on Mount Maunganui main beach, Thomas says about 20 surfers are visible and three kayakers are in the water off the coast.

'Surfing conditions are actually really good, there is about a five to six foot swell.”

Thomas says onlookers are enjoying watching the rough conditions with about 80 people gathered on the beach.

He says they are trying to keep people off the high tide mark as small amounts of oil have been seen washing up along the coast.

'There is a little bit of polystyrene coming up along the beaches.”

The beach itself is open but people are being advised to stay out of the water.