The cost of council tax rebates for flooding victims will be paid for by the Treasury, David Cameron has confirmed.
Some local authorities have already announced plans to exempt residents forced out of their homes from part or all of the bill.
The Prime Minister, who is visiting West Wales on a tour of flood-hit parts of the UK, said councils which make the move will not lose out.
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Labour strongholds tended to remain so - apart from a major loss for the party in Dudley.
Labour suffered a "terrible" defeat in Rhondda but has already won 16 Welsh Assembly seats as it looks to record a fifth term in office.
UKIP have made further gains in the local elections in the Anglia region and the Conservatives have won back control in Peterborough.