Flooding and disruption to travel is possible in Morocco with further heavy rain forecast for many parts of the country until Saturday.
The warning came in an updated travel advisory from the Foreign and Commonwealth Office.
At least 32 people are already known to have died in devastating floods, and more are still missing.
“Heavy rain has caused flash flooding in some areas of south Morocco including in the regions around Marrakech and Ourzazate. Some roads and other routes in rural areas have been closed,” the FCO said.
People travelling in the regions between Safi, Taroudant and Guelmim are being advised to follow the advice of local authorities and guides, and monitor local media.
Walking and driving can be dangerous in flooded areas, the FCO added.
More than 400,000 Britons visit Morocco every year.