TOKYO (REUTERS) - Work to remove spent fuel rod assemblies from Japan's destroyed Fukushima reactor has been halted after possible damage to a giant crane, the first major delay in an operation to remove 1,533 fuel assemblies from a holding pool.

Plant operator Tokyo Electric Power Co (Tepco) has been retrieving highly irradiated spent fuel rods from the No. 4 reactor building at the Fukushima nuclear plant, which was hit by a massive earthquake and tsunami in 2011.

Fuel retrieveal was halted after a worker started moving a crane used to lift the fuel assemblies out of the pool without disengaging the handbrake on Wednesday, generating a warning alarm, a Tepco spokesman said.

Workers and the crane's manufacturer were inspecting the equipment and hoped to restart operations as soon as possible.

Tepco has floundered for much of the past 2-1/2 years in dealing with problems at the site, including a series of leaks of radioactive water from hastily built tanks at the site.

The delicate task of removing the fuel assemblies - each weighing about 300kg and containing 50 to 70 fuel rods - began last November and has won the company rare praise.

Some 550 fuel assemblies have been removed so far and Tepco hopes to complete the operation by the end of the year.