Labour MPs from across Wales have rounded on the Government to attack the so-called bedroom tax and changes to housing benefits.

Shadow Welsh Secretary Owen Smith used Welsh Questions to attack the policy that Ed Miliband last month pledged to repeal if Labour wins the 2015 general election.

The Pontypridd MP said: “The Government’s own impact assessment states that 46% of households in social housing in Wales have been hit by the bedroom tax, which is a higher proportion than anywhere else in Britain. Those are the Government’s own numbers.

“The bedroom tax will also hit 25,000 disabled families... It is not working for those 25,000  people – 25,000 reasons why we need a Labour Government to scrap the bedroom tax and deliver justice for those people in  Wales.”

Wales Office minister and Preseli Pembrokeshire Conservative MP Stephen Crabb defended the policy, which cuts housing benefit if social tenants are judged to have more than the allocated number of bedrooms.

He denied that Wales was “hit harder” than other parts of the UK and said an extra £7m in discretionary housing payments had been made available in Wales to help people adjust to the new rules.

He said: “On top of that, we are making money available for rural borough councils in Wales to assist with the transition.

"We recognise that it is a challenge and a difficult period for people going through our changes to housing benefit, but we are supporting local authorities in Wales to help Welsh people through that transition.”

Alyn and Deeside Labour MP Mark Tami argued there were not enough properties with a smaller number of people to move into.

He said: “Will the minister advise me where he thinks Flintshire council and other local authorities are supposed to find these mythical one and two-bedroom properties? While he is at  it, why does he think it is a good idea to force disabled people out of homes that have been adapted by councils at high cost?”

Mr Crabb replied: “We are not forcing disabled people out of their homes. On [his] question about Flintshire, we are making available to his local authority more than £240,000 this year in discretionary housing benefit. I ask him to ask his local authority why it has more than 275 empty properties in the social rented sector.

“That is part of the answer to the local housing problems in Flintshire.”

Swansea West Labour MP Geraint Davies followed up the attack, claiming that “in Swansea two thirds of the thousands of people affected by the bedroom tax are now in arrears and that those arrears have doubled since April”.

He added that the policy resulted in “the poor being thrust into dire poverty and the arms of loan sharks”.

Mr Crabb said there were approximately 300 empty properties in the social rented sector in Swansea, adding: “I am concerned to hear about the large increase in the number of people he says are suffering from rent arrears.

"We are making available substantial resource to Swansea borough council, and we should be asking how it is using those discretionary housing payments to  assist people through the difficult transition.”

Montgomeryshire Conservative MP Glyn Davies argued the Welsh Government could not escape blame for the situation.

He said: “One of the best ways to help those affected by changes in housing benefit is through the provision of new single-person housing, but that has not been helped by the reduction in social housing built by the Welsh Government or by the extra Welsh-specific building regulations, which have impacted on the private sector and driven it out of Wales altogether.”

Mr Crabb said: “The Welsh Government are responsible for the supply of new housing in Wales, and I think that serious questions need to be put to Welsh Ministers in Cardiff about that.”

Welsh Secretary and Clwyd  West Conservative MP David Jones also fired a shot down the M4, suggesting the Welsh Development Agency – axed during former First Minister Rhodri Morgan’s “bonfire of the quangos” – should be revived to boost exports.

He said: “There were modest  improvements recently, but it is the case that the Welsh Assembly Government should give serious consideration to reinstating a body like the Welsh  Development Agency, which was so successful.”

Calling for greater cooperation between Welsh businesses and the UK Trade & Investment, he said: “Wales is largely a country of small and medium-sized enterprises, and if more SMEs were to export at the European rate, that would wipe out the  trade deficit altogether.

"I strongly encourage Welsh companies to engage closely with UKTI, as it has global reach and is able to maximise opportunities throughout Europe and the rest of the world.”