Tropical Storm Emily killed four people in the Dominican Republic and Haiti, authorities said on Friday, as remnants of the storm drifted over the Caribbean with a "high chance" of restrengthening into a tropical cyclone.

Emily, the fifth named storm of the 2011 Atlantic hurricane season, dissipated Thursday as it approached mountainous Hispaniola island, which is shared by Haiti and the Dominican Republic.

The storm's leftovers posed no threat to oil and gas production facilities in the US Gulf of Mexico, and most forecasts showed the system keeping well off the southeast US coast.

But authorities said Emily could still pack a punch after its heavy rainfall killed three in the Dominican Republic, two of whom were swept away by a swollen river in Higuey, a small town about 100 miles (160 km) east of the capital Santo Domingo.

At least one other person died in neighboring Haiti in flooding in the sprawling southern city of Les Cayes.

Thousands of Dominicans and Haitians were forced to evacuate their homes because of Emily, with dozens of villages cut off by floodwaters, officials said.

The US National Hurricane Center said the weather system that spawned Emily remained mostly disorganized Friday, as it hovered nearly stationary midway between the north-central coast of Cuba and the central Bahamas.

But conditions were gradually becoming more conducive for the system to restrengthen.

"This system has a high chance, 70 per cent, of regenerating into a tropical cyclone during the next 48 hours," the Miami-based hurricane center said. It had earlier pegged the chances of Emily's re-birth at 60 per cent.

Forecasters are predicting a busier-than-average hurricane season this year.

On Thursday the US government weather agency NOAA raised its outlook for activity in the 2011 Atlantic hurricane season, predicting it would produce seven to 10 hurricanes.

Three to five of those were expected to strengthen into "major" hurricanes of Category 3 or higher on the five-step Saffir-Simpson intensity scale, with top winds of at least 110 miles (178 km) per hour, it said.

In May, NOAA projected six to 10 hurricanes. – Reuters