Saudi Arabia vowed to improve infrastructure in the second-largest city Jeddah after floods swept through the major port and killed 10 people, triggering rare protests among residents complaining of neglect.

Last Friday, authorities detained dozens of residents protesting against poor infrastructure in a country that has billions to spend on infrastructure as the world's largest oil exporter.

According to official figures, floods damaged more than 90 per cent of Jeddah's roads and some 27,000 buildings last week, adding to woes of residents who have long complained about the lack of sewage in a city of four million.

King Abdullah bin Abdul-Aziz, who is recuperating in Morocco after undergoing medical treatment in New York, set up a committee to hire foreign firms to improve the infrastructure to avoid future floods, state news agency SPA said late on Tuesday.

Interior Minister Nayef bin Abdul-Aziz, a key royal, also said the government would launch an investigation and punish those responsible for floods.

'What happened in Jeddah has shown negligence and mistakes,' said Nayef, who is also second deputy prime minister.

'There are intentional mistakes resulting from delinquency and unintentional mistakes, and this will not be ignored at present or in future.'

SPA said more than 4,923 families and 18,027 individuals were evacuated during the floods last week when some streets were submerged under four meters of water in housing areas built in valleys.-Reuters