Britain's government has promised more than £40mn ($59mn) to rebuild and improve the country's flood defences that failed to protect thousands of homes over the Christmas holidays.

Homes and businesses across northern England, Scotland and northern Ireland were hit by storms and torrential rains in December, leaving many without electricity and some under metres of water after river levels reached all-time highs.

Prime Minister David Cameron has been criticised by opposition lawmakers for not doing enough to protect the country from severe weather and the Observer newspaper on Sunday said many of Britain's flood defences were being abandoned or maintained to minimal levels because of government cuts.

In a statement, Cameron announced a package of more than £40mn to improve flood defences after Storm Eva brought gales and torrential downpours to Northern Ireland, Wales, England and parts of Scotland in late December.

"I have seen at first-hand the devastation caused by flooding. And that's why this work to repair and improve flood defences is so vital," Cameron said in the statement.

He said £10mn would be used to improve the Foss barrier protecting the northern English city of York, which was overwhelmed at the height of Storm Eva. The other £30mn would be spent on defences on other rivers in northern England.

The government would also support charities helping those caught up in the deluge by matching every pound of the first £2mn raised, he said.

The opposition Labour Party accused the government of complacency and said the funding would not go far enough.

"The government has been woefully complacent about the flood risk, ignoring warnings from its own experts," Kerry McCarthy, Labour's Environment, Food and Rural Affairs spokeswoman, said in a statement.

"Today's announcement of £40mn won't go very far at all ... a lump sum of £40mn is a short-term, sticking-plaster approach."

The Observer quoted a document submitted to ministers late last year that said investment in Britain's flood defences had fallen despite the country seeing "the five wettest years since 2000".

On Saturday, Britain's Meteorological Office issued an "amber warning" for potentially heavy rain in eastern Scotland at the weekend and on Monday which could lead to some flooding.