Huge tailbacks snaked along six-lane expressways after up to 254 millimetres of rain -- about two years' worth -- fell on the desert United Arab Emirates on Tuesday.

At least one person was killed after a 70-year-old man was swept away in his car in Ras Al-Khaimah, one of the country's seven emirates, police said.

Passengers were warned not to come to Dubai airport, the world's busiest by international traffic, "unless absolutely necessary", an official said.

"Flights continue to be delayed and diverted... We are working hard to recover operations as quickly as possible in very challenging conditions," a Dubai Airports spokesperson said.

Dubai's flagship Emirates airline cancelled all check-ins on Wednesday as staff and passengers struggled to arrive and leave, with access roads flooded and some metro services suspended.

At the airport, long taxi queues formed and delayed passengers milled around. Scores of flights were also delayed, cancelled and diverted during Tuesday's torrential rain.

The storms hit the UAE and Bahrain overnight Monday and on Tuesday after lashing Oman, where 18 people were killed, including several children.

Climatologist Friederike Otto, a specialist in assessing the role of climate change on extreme weather events, told AFP it was "high likely" that global warming had worsened the storms.

Official media said it was the highest rainfall since records began in 1949, before the formation of the UAE in 1971.