Two more people have been confirmed dead in Texas in the wake of Storm Harvey, bringing the number of known fatalities to 44, eight days after it made landfall as a hurricane.

A curfew has been imposed in Houston where more than 13,000 people have been rescued after a catastrophic storm that is now the heaviest tropical downpour in US history.

Taking a cue from the suffering in New Orleans, residents lined up for plywood and officials called for a voluntary evacuation of the island city of Galveston as Hurricane Rita threatened to slam into the Texas Coast this weekend.