Tropical Storm Rafael churns towards Cuba

Tropical Storm Rafael has gained steam as it churned northward towards Cuba, which is still struggling to recover from a nationwide blackout and hurricane two weeks ago.

The US National Hurricane Center said Rafael would see "steady or rapid intensification" before ploughing across western Cuba with maximum predicted winds of up to 160km/h by Wednesday.

The Miami-based forecaster also warned of dangerous storm surge and destructive waves in the Cayman Islands, and said Rafael would intensify further late on Tuesday before heading towards Cuba.

The timing could not be worse for the Communist-run island, which in October suffered a collapse of its national electric grid, leaving an estimated 10 million people without power for several days.

Many of the island's residents still face hours-long outages daily due to generation shortfalls.

Hurricane Oscar hit Cuba about the same time as the blackout, throwing a one-two punch that has sapped precious resources in a country suffering from severe shortages of food, fuel and medicine.

Rafael is predicted to pass near the capital Havana.

Its decrepit and antiquated housing and infrastructure are particularly vulnerable to strong winds.

Authorities have already evacuated more than 66,000 Cubans from far-eastern Cuba, in Guantanamo province, ahead of predicted heavy rains and flooding early this week. Soils in the province were saturated by flooding and damage from Oscar, the government said.

Plans were under way to evacuate thousands of residents in Pinar del Rio province, on the island's far-western end.

Several Cuban provinces had partially or fully suspended classes, and the transport ministry had begun cancelling some bus and train routes, officials said.

The government encouraged residents, many still largely without communication because of power outages, to dial a government emergency phone number to follow the storm's progress.

The NHC said much of Cuba's western half was under a hurricane watch, but warned that the storm's eventual track over the Gulf of Mexico, towards the United States, remained uncertain.

The system is about 280km south of Kingston, Jamaica, packing maximum sustained winds of 75km/h.