The spokeswoman for a local emergency services coordinator confirmed: "Five people including two British nationals have died".
A former mayor of the town of Arta near Sant Llorenc des Cardassar which was worst affected by the floods has also been named as one of the five fatalities.
The UK's Foreign Office said it was "urgently seeking updates" from Spanish authorities, according to the BBC, amidst fears of additional casualties among British nationals.
The town of Sant Llorenc is around 60 kilometres east of Palma - the capital of the Mediterranean island.
In just two hours, some 180 litres of rain fell and we realised that we could not control the water.
Image Heavy rain and flash floods hit Sant Llorenc de Cardassar on the island of Mallorca Spain
Majorca was hit by devastating floods overnight.
The British couple believed to have been killed were said to be travelling in a taxi when the vehicle was caught in the flood.
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 weather agency, AEMET, said more heavy rainfall is expected Wednesday in eastern and southern parts of the Iberian peninsula. The flooding also affected phone communications, destroyed two bridges and forced the closure of 11 roads.
He was planning to travel to the area later on Wednesday, his office said.
Lawmakers held a minute's silence before the weekly prime minister's question time in parliament on Wednesday morning. Streets in towns near Malaga on the Costa del Sol experienced flood water which was several feet deep.
Kate Middleton Rewears Gorgeous Lilac Dress From Last Year
The Duke and Duchess had a chance to speak to young delegates at the summit about the challenges and issues they face. Kate and Will chose a mental health summit as their first royal engagement after the Duchess' maternity leave .
MI man's doorstop is $100,000 meteorite
A farmer who'd used a 23-pound rock as a doorstop since 1988 has learned that it's actually a meteorite worth $100,000 (£76,000). As the new owner of the property, the man was told that the rock was a part of the property and that he could have it.
Crude oil prices may have peaked
The IMF, however, predicted Iran's economy will sink deep in the red due to renewed United States sanctions. Washington said on Friday it was considering waivers for nations that were reducing imports of Iranian oil.