The cost of council tax rebates for flooding victims will be covered by the Treasury, David Cameron has confirmed.
Some local authorities have 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 as he continues to tour all flood-hit parts of the UK, said councils which make the move will not lose out.
He tweeted: "I can confirm we will fund councils that give council tax rebates to people whose homes have been flooded."
A £4 million fund will be made available to councils to cover the bill for giving residents a rebate while they are out of their homes but it will be up to local authorities to decide how the scheme would work.
Councils will not be forced to introduce the payment exemptions but a No 10 source said the "funding is there so there is no reason why it should not be taken".
They added: "We are sure councils will be very eager to do all they can."
Somerset County Council has already announced plans to suspend the county council part of the tax for residents affected by the flooding and Aylesbury Vale District Council i n south Buckinghamshire said households can apply for a 100% reduction in the fee.
During a visit to Pembrokeshire, the PM said flood defences in Wales were the Welsh Assembly Government's responsibility.
"The primary responsibility for flood defences is the Welsh Assembly government, that's the devolution settlement," he told Sky News. "But always happy to talk about particular problems, particular things that need to be done."
Shadow communities secretary Hilary Benn said: " The Government should admit that it was a mistake to have changed the law to take away the former provisions giving automatic council tax exemptions when properties are empty and require repairs to make them habitable in cases of flooding.
"In 2007 Labour provided additional funding to help provide council tax exemptions for those households forced to leave their homes for over a year.
"The Government needs to reassure residents that they will work with local authorities to ensure flood victims are not paying council taxes on properties needing substantial repairs."
The funding pot is open to English councils and comes alongside business rate relief for flood-hit communities.
Local Government Minister Brandon Lewis said: "This Government is funding both council tax and business rate relief on flood-hit properties. Councils have the discretion to offer local tax discounts, and it's right to use them.
"But the Labour Party are in disarray on their policy on empty homes. On Monday, Ed Miliband called for higher council taxes on empty homes, today Hilary Benn wants to keep tax subsidises for empty homes. Labour are jumping from bandwagon to bandwagon."