Battered Caribbean islands in way of second hurricane

Buildings destroyed by Irma in St Martin. Photo / AP

A second powerful storm in as many weeks is bearing down on a string of battered Caribbean islands, with forecasters saying Maria will strengthen rapidly into a major hurricane in the next two days.

It is expected to rip into the Leeward Islands today.

Maria's strength was building as it approached the Lesser Antilles, the US National Hurricane Centre said, estimating its winds at near 140km/h.

"Maria is expected to become a major hurricane as it moves through the Leeward Islands," the forecaster said.

Maria is approaching the eastern Caribbean less than two weeks after Irma hammered the region before overrunning Florida.

That storm, one of the most powerful ever recorded in the Atlantic with winds up to 298km/h, killed at least 84 people, more than half of them in the Caribbean.

Hurricane conditions were expected for Guadalupe, Dominica, Martinique and St. Kitts, Nevis and Montserrat, and the hurricane centre is warning Puerto Rico to monitor the storm.

The British Virgin Islands and St Martin, which was devastated by Hurricane Irma, were under a hurricane watch, as were the US Virgin Islands and Anguilla.

More than 1700 residents of Barbuda, where Irma damaged nearly every building, braced for Maria on Antigua, now under a tropical storm watch, said Ronald Sanders, the country's ambassador to the United States.

Puerto Rico has already begun preparations for Maria, which by Wednesday was expected to unleash powerful winds on the US territory, already dealing with a weakened economy and fragile power grid.

Damage to Puerto Rico could also disrupt the disaster relief supply chain to other islands that were hit by Irma.

"Puerto Rico is our lifeline," said Judson Burdon, a permanent resident of Anguilla who has helped coordinate supply shipments to the island.

The planned deliveries consisted of plywood, power tools and screws to close up windows and doors that remain open on the island, where 90 per cent of structures were damaged.

The centre of storm was about 165km northeast of Barbados and about 340km east-southeast of the Leeward island of Dominica.

A tropical storm watch has also been issued for portions of the US mid-Atlantic and New England coast with a second hurricane, Jose, moving slowly north from its position in the Atlantic Ocean about 510km southeast of Cape Hatteras, North Carolina.

The eye of Jose, with top sustained winds of 150km/h, should remain off the US East Coast, the NHC said.

- Reuters, AAP