Kaikoura's surfers are anxiously waiting for a swell to see what the weekend's earthquake means for the region's famous surf breaks.

Stunned locals found that the sea bed had lifted by at least a metre after the quake, leaving the sea floor exposed and killing countless paua, crayfish and seaweed.

It's a potential disaster for local fishers, and now Kaikoura's many surfers and surfing businesses can only wait to see whether it will destroy or improve its existing breaks - or create entirely new ones.

Local surfer Matt McCrory said there had been no swell since the earthquake but that was due to change with a southerly blowing in.

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"At the moment it's raining and it's terrible but there will be swell after this and we'll definitely get some insight into what's going to happen with the surf breaks, once the southerly passes."

McCrory was more optimistic than worried.

"You've probably seen the photos of how everything jumped out of the ocean ... so I'm really optimistic and hopeful that we've got some new surf breaks.

"I'd say it's going to be a real game-changer for the town surf-wise either way."

He said several river mouths had also shifted in the quake, which was bound to have some impact on the surf.

Ben Kennings of Surfing NZ said the Kaikoura surfers he'd been in contact with were waiting anxiously for signs from the sea.

"It could go either way I guess. Both Mangamaunu and Meatworks are protected under the coastal policy statement so I guess that gives an indication of their value as surf breaks to tourism and as natural resources.

"It's a place surfers love to stop in at when they're travelling around the country, and of course it's really important to the locals. There's a surf school down there and a few surf shops so this could impact a lot of people," Kennings said.

There had been cases overseas, notably in Indonesia, where surf breaks improved "immensely" following earthquakes.

"Or it could go the other way and it could ruin the breaks, or a new break could come along."

Kaikoura boasts much-loved point, reef and beach breaks at Mangamaunu, Kahutara, Meatworks, Graveyards and Okiwi Bay - essential stops on the New Zealand surfer's itinerary.

Dr Joshu Mountjoy, a marine geologist at the National Institute of Water and Atmospheric Research, said at this stage their data couldn't provide any insights into what the raised sea floor would mean for the surf breaks. The earliest analysis would come from the surfers themselves when a swell arrived.

"The data really is yet to be collected to understand the full distribution of the uplift. I personally am familiar with the breaks and share [the locals'] concerns because they're amazing.

"I really don't know how this will affect them, it could go either way. The whole coastline is going to have changed to some degree."