Antonia Bauza, the deputy mayor of Sant Llorenc, confirmed two of the victims were British nationals.
A spokeswoman with the regional emergency service said two British nationals and a Dutch woman were among the victims, but she couldn't confirm whether six more people were still missing at midday as local media reported.
Footage broadcast on Spanish television on Wednesday showed cars being swept away by raging, muddy waters, houses flooded and vehicles piled one on top of the other after the Mediterranean island was pounded with heavy rain in just a few hours.
Majorca was hit by devastating floods overnight.
A sports centre - the Miguel Ángel Nadal sports centre in the town of Manacor - has opened its doors to give shelter to local people whose homes have been damaged.
The British pair reportedly died in a taxi in the Sant Llorenc area of this island after strong torrents formed during intense showers.
100 rescue workers have been deployed to the area, and will be joined by 80 soldiers. The flooding also affected phone communications, destroyed two bridges and forced the closure of 11 roads.
"My solidarity and support goes out to the families and friends of victims and all those affected by these tragic floods", Prime Minister Pedro Sanchez said on Twitter.
Sanchez will be flying to the area later Wednesday, his office said.
A spokesperson for the Spanish government's office in the Balearic Islands told AFP news agency that nine people died in the floods. Streets in towns near Malaga on the Costa del Sol experienced flood water which was several feet deep.