Powerful Hurricane Beryl churned towards Jamaica on Wednesday with dangerous winds and sea surge, as residents hunkered down against a storm that has killed seven people and caused destruction in the Caribbean.

The hurricane – unusually strong so early in the Atlantic season – was expected to pass near or over Jamaica by midday as a life-threatening Category 4 storm, meteorologists said.

Beryl is the first storm since US National Hurricane Centre (NHC) records began to reach the Category 4 level in June and the earliest to reach Category 5 in July.

Across Jamaica, people removed boats from the water and tied them to fences for safety and rushed to buy food, water, petrol and other essentials.

As of Wednesday morning the storm was packing maximum sustained winds of 235 kilometres per hour, said the NHC.

Prime Minister Andrew Holness declared an island-wide 6 am to 6 pm curfew.

Desmon Brown, manager of the National Stadium in Kingston, said his staff has tried to be ready.

"We're doing the usual, removing all objects that can cause damage," he told the Jamaica Observer newspaper.

"We've taped up our windows, covered our equipment – including computers, printers and that sort of thing. Apart from that, it's mainly concrete so there's not much we can do," Brown said.

Rain from the outer bands of Beryl started pounding Jamaica overnight on Tuesday into Wednesday.

Hurricane warnings were also issued in the Cayman Islands further west, which Beryl was expected to pass near or over on Wednesday night or early on Thursday, according to the NHC.

Beryl has already left a trail of death with at least three people killed in Grenada, where the storm made landfall on Monday, as well as one in St Vincent and the Grenadines and three in Venezuela. (AFP)