The monster Category 5 storm is the largest to have ever formed in the Atlantic with winds of 185mph.
Irma is tracking west towards a number of Caribbean islands including Antigua, St Kitts and Nevis, the British Virgin Islands, Puerto Rico, Dominican Republic and Cuba. Florida is also in the path of the hurricane.
The Foreign Office advice for the Dominican reads: "Hurricane Irma is forecast to bring hazardous sea and weather conditions to northern parts of the Dominican Republic from around Wednesday 6 September 2017.
"You should follow the advice of the local authorities and any evacuation orders."
A number of British airlines including British Airways have cancelled flights to the region. Others are assessing the situation.
As well as fiercely strong winds Hurricane Irma is also set to dump around 18 inches of rain on parts of the Caribbean. The storm will also create a huge surge of seawater with levels rising by up to 20 feet in some places.
For the latest advice, see the Foreign Office website.