TROPICAL Storm Matthew formed on Wednesday morning in the eastern Caribbean and lashed several islands with heavy wind and rain.

A tropical storm warning was in effect for much of the southernmost islands of the Lesser Antilles, including Barbados, Dominica, St Lucia, St Vincent and the Grenadines and the French islands of Guadeloupe and Martinique.

Authorities closed the international airport in Barbados and officials in St Lucia advised businesses to close for the day as the storm passed. There were no immediate reports of any injuries or major damage.

The US National Hurricane Center (NHC) in Miami said Matthew had sustained winds of 60mph and was expected to bring rainfall of four to eight inches to the northern Windward Islands and the southern portion of the Leeward Islands. The NHC warned that the heavy rain could trigger flash floods and mudslides.

Matthew was centred about 35 miles east-northeast of St Vincent and was moving west at 21mph at 11am on Wednesday. The storm was on track to pass through the southern Caribbean before heading north across the eastern Caribbean Sea in the next two days.

Gradual strengthening is forecast and Matthew could become a hurricane by Friday.