A cyclone in the Bay of Bengal is expected to slam into the coast of southeast Bangladesh and Myanmar within a day, a government meteorologist warned Thursday, as officials met for urgent talks.

The warning came less than six months after cyclone Sidr caused massive devastation in southern Bangladesh, leaving more than 3,000 people dead.

"Cyclone Nargis is intensifying and is heading towards the coast," said Shah Alam, assistant director of the Meteorological Department, adding it was likely to hit the coast of Bangladesh's Cox's Bazar district and neighbouring Myanmar from Friday afternoon.

Disaster management ministry officials had been summoned to an urgent meeting to assess the potential danger, an official told AFP.

Alam said the cyclone was moving at a maximum speed of 115 kilometres (71 miles) per hour, about half the speed of Sidr.

"We think it will hit about 150 kilometres (93 miles) of the Bangladesh coastline and 150 kilometres of the Myanmar coast," he added.

The department had issued warning signal four for Cox's Bazar and Chittagong coastal districts, indicating that a storm was expected but that extreme precautionary measures were not yet required.

Fishing crews have already been told to stay close to the shore and not to venture into the Bay of Bengal.

Half a million people perished in a cyclone in 1970. Some 138,000 died in 1991 in a tidal wave caused by a cyclone.