Hurricane Dorian has intensified to a Category 5 storm, capable of inflicting catastrophic levels of destruction, The National Hurricane Centre has warned in it's latest forecast.

Dorian's maximum sustained winds have increased to 260 km/h, up from 240 km/h. It is moving west at 13 km/h.

"Devastating hurricane conditions" are expected in the Abacos Islands early Sunday, with conditions spreading across Grand Bahama Island later in the day, the centre said.

The storm's centre is approximately 55 kilometres east of Great Abaco Island and 225 360 kilometres east of West Palm Beach.

An image of Hurricane Dorian from space. (NASA)

Residents and tourists in the Bahamas have been urged to seek shelter as time runs out before the powerful storm hits, with authorities warning those who refuse to move are risking their lives.

"Hurricane Dorian is a devastating, dangerous storm approaching our islands," Bahamas Prime Minister Hubert Minnis said in a nationally televised news conference.

People in Florida, Georgia, South Carolina and North Carolina were told to prepare for its arrival late on Monday at the end of a long holiday weekend.

Hurricane Dorian bore down on the Bahamas as a fierce Category 4 storm today. (AP)

Florida Governor Ron DeSantis declared a State of Emergency on Thursday and said some areas should prepare to evacuate.

Swells that are likely to cause life-threatening surf and rip current conditions are expected begin to affect Florida's east coast and the south-eastern US over the next few days, the NHC said.

In its direct, immediate path the monster storm was headed for the Bahamian northwestern islands of Grand Bahama and Abaco.

Dorian is packing 240km/h winds, and forecasters predict it will flirt with top-of-the-scale Category 5 wind speeds of 250kph later in the day as it menaces the Bahamas. (AP)

Minnis said that 73,000 people and 21,000 homes were at risk to storm surges of up to 4.6 metres.

"Dorian will now create prolonged periods of large swells, surges along the north coast of Grand Bahama and the north and east coast of Abaco," Jeffery Simmons, the deputy director of Bahamas' department of meteorology, said.

"We are asking residents in those areas to leave the coastline, we expect a storm surge of up to 15 feet, in addition to that we have a spring tide that can increase the surge by 2 to 3 feet," Simmons added.

Supermarkets have run out of bottled water, and long lines formed at gas stations, with some fuel shortages reported. (PA)

Florida Governor Ron DeSantis warned residents not to let their guard down. (PA)

Once the storm unleashes its fury on the archipelago nation, people will have to ride out Dorian before first responders can venture outside to rescue anyone.

Rescue workers "will not be able to move with 145 or 150 mile per hour winds ... so those individuals that want to move I advise that they move now," said Minnis.

Grand Bahama and Abaco are hubs for the Bahamas' thriving tourism industry. The nation owes nearly 30 per cent of its direct gross domestic product and half of its jobs to the industry, Joy Jibrilu, director general of the Ministry of Tourism, said.