Officials from Japan's Fisheries Agency are surveying a fishing port on the Noto Peninsula, where a powerful earthquake on New Year's Day lifted the seabed.

Fishing boats have been unable to go into or out of some ports on the peninsula in Ishikawa Prefecture, central Japan, because the water is now too shallow.

Noroshi port in Suzu City is controlled by the prefectural authorities, but work to fix it will be carried out by the central government.

On Wednesday, Fisheries Agency officials began measuring the depth of water at the port.

The procedure involves using a laser on an aerial drone to measure the time lag between reflection on the water surface and on the seabed.

The readings show that water near the quay, which used to be 4.5 meters deep, is now about 1.5 meters shallower.

Some locations near the breakwater were found to be too shallow even for small boats.

Noroshi port had been made deep enough for 500 ton-class fishing vessels, because it is designated a harbor of refuge in case of rough seas.

Following the survey, the agency plans to dig or dredge areas that have become shallow.

One official said the team hopes to apply knowledge acquired through the work at Noroshi to restoring other ports.

He said the agency want to make the port useable for fishers even if it is step by step.