About 30 people are missing after six houses collapsed in the western German state of Rhineland-Palatinate due to flooding and heavy rain, broadcaster SWR says.

About 25 more houses are at risk of collapsing in the district of Schuld bei Adenau, in the hilly Eiffel region, SWR added, citing local police following Wednesday night’s collapses.

Two firefighters drowned and the army was deployed to help stranded residents on Wednesday, after a slow-moving low-pressure weather system caused once-in-a-generation floods.

Among them is a family-of-five whose home is completely surrounded by water, a spokesman for the district told broadcaster SWR.

Some residents in Altenahr have resorted to climbing onto their roofs as they wait to be rescued.

Rail, road and river transport was disrupted with shipping suspended on the Rhine river.

Those in areas within a 50-metre radius of the Ahr river have been evacuated.

Heavy rainstorms could be expected in south-western Germany on Thursday, with continuous rains until Friday night, the German Weather Service warned in a morning bulletin

-more to come

-with AAP