A digger has been pulled from the surf on the Kapiti Coast.

It took two bulldozers and a large digger to rectify what is being described as a drunken prank - and now police are trying to track down the culprits.

A 25-tonne digger was spotted in the Kapiti Coast surf before dawn on Saturday.

Shortly after midday, the digger, estimated to be worth about $250,000, was hauled to dry land by two bulldozers, another digger and long lengths of steel cable.

FAIRFAX NZ A cable is attached to the digger, which is sucked to the sea floor.

A large crowd, easily more than 100 people, gathered to watch the rescue effort north of Wellington.

Ross Dolman, a spectator at the scene, but a digger driver by trade, said the 25-tonne digger would be worth about $250,000.

He understood someone found some keys and managed to get the digger going in the middle of the night and drove it away from the nearby boating club it had been parked outside.

FAIRFAX NZ Workers ponder the watery predicament.

It was not clear if the digger had got swamped in the sea or "if they decided to park it there just for a bit of a laugh", he said.

"It's going to be some pretty unhappy contractors around."

Police say they're "making enquiries" but there have been no arrests yet.

FAIRFAX NZ A 25 tonne digger has been hauled from the Kapiti Coast surf after it was discovered there Saturday morning.

They're keen to hear from any members of the public who saw anything suspicious in the area not long after midnight Friday - in particular, any sightings of the driver of a silver car.

When people arrived to save the digger it was sinking into the soft mud and the outgoing tide was creating a suction to the sea floor.

It meant workers - braving cold, rain , and surf - had to get the steel cables beneath the machine and the force of the two bulldozers and digger were needed to break the powerful suction.

"It's going to be a big effort," he said while the digger remained stick.

"They have got all the knowledge and all the gear."

Shortly after - with one of the rescue bulldozers also sinking deep in the mud - the stranded digger was hauled from the sea.

Police said they were notified at 5.10am on Saturday "that there was something resembling a digger in the surf" off the beach at Paraparaumu.

It was not clear how it got there and the Kapiti Coast District Council have been notified.

A person who spotted the digger believed it could have been a drunken prank.