Dorian is now a category 5 hurricane with 160 mph sustained winds, officials said. (File)

Hurricane Dorian strengthened into a catastrophic Category 5 storm Sunday, packing 160 mph (267 kph) winds as it was about to slam into the Abaco Islands in the Bahamas, US weather forecasters said.

"#Dorian is now a category 5 #hurricane with 160 mph sustained winds," the Miami-based National Hurricane Center said in a tweet.

"The eyewall of this catastrophic hurricane is about to hit the Abaco Islands with devastating winds," it said.

The slow moving storm was expected to linger over the Bahamas through Sunday and much of Monday, dumping up to 25 inches of rain in some areas and unleashing storm surges of 10 to 15-feet, forecasters said.

"If you're watching anybody in the Bahamas a very dangerous, dangerous situation," said Ken Graham, the NHC's director.