German prosecutors have said they are examining a possible manslaughter investigation arising from failed or delayed warnings about July's deadly floods.

186 people lost their lives in severe floods that pummelled western Germany in mid-July, raising questions about whether enough was done to forewarn residents.

Prosecutors said they were looking at whether there were grounds to launch investigations into "negligent homicide and negligent bodily harm as the result of possibly failed or delayed warnings or evacuations of the population".

Among the evidence are police reports on the deaths of 12 people at a care facility in the town of Sinzig where the ground floor had been swiftly inundated, leaving no time for the residents to be safely evacuated.

The Frankfurter Allgemeine Zeitung reported that local authorities in Ahrweiler had been warned about the impending flood by the state's environmental office in the afternoon of 14 July.

At 9.30pm, the authorities were informed that the gauge would hit almost seven metres, but they declared a disaster only 90 minutes later, ordering a partial evacuation of the region.

Heinz Wolschendorf, who was in charge of rescue services in the worst-hit region of Ahrtal in Rhineland-Palatinate state, has defended the emergency deployment.

"We did everything that was possible to support the population and carry out the rescue operations," he said.
Interior Minister Horst Seehofer last week said Germany will issue mobile phone text alerts in the future to inform citizens of impending dangers.

Twenty-six people are still missing after torrents of water ripped through towns and villages, destroying bridges, roads, railways and housing in the region's worst flooding disaster in living memory.