Jackie Lawrence MP

The move comes after the planning authority claimed it has reached "environmental planning capacity".

The ban is seen as a measure to halt the number of holiday and retirement homes which are blamed for pushing up house prices.

However, a former chairman of Pembrokeshire County Council has criticised the plan, under which applications for new homes will only be considered if there is a proven local need .

"I am opposed to it as it is a blanket refusal," said Councillor Alwyn Luke.

"Where are people going to build? We can't accommodate them in the villages and towns around the national park."

"I'd like to think this goes further to consultation and that we as local people have a further say before it is implemented," he added.

But Ms Lawrence argued it will cater for local needs and essential services.

"I think the park has taken a very positive step to protect communities," said Ms Lawrence.

English plans

It is believed this is the first such decision made by a Welsh planning authority.

However, similar policies have already been adopted by English national parks such as Exmoor, the Peak District and the Lake District.

Councillor Alwyn Luke

"National Parks are about the landscape, but it is important to keep balanced communities in those areas," said Jack Ellerby, principal planning officer for policy and community in Exmoor.

"We are ahead of Pembrokeshire as we have published our draft policies on housing for consultation and are analysing what people have said," added Mr Ellerby.

"We learnt from the Peak District and the Lake District, and have written in some local needs housing policies which, I believe, Pembrokeshire is trying to follow."

Language communities

All future applications for new homes will have to prove a need for residential accommodation for local people.

This will be based on either a three year residency qualification, family connections, previous residency or previous or current employment.

It is estimated that the national park receives an average of 100 such applications annually and it is envisaged that the number of future recommendations of such applications will be reduced drastically.

Pembrokeshire National Park

The move is seen as an attempt to curtail the number of holiday and retirement homes within the national park as well as speculative building.

Pembrokeshire National Park stretches from Tenby in the south through St David's and Newport as far north as the outskirts of St Dogmaels - a distance of 180 miles.

The policy refers to the need to protect what are described as sustainable communities as well as Welsh language communities.

However, a spokesman for the Welsh Language Society stressed it is not a linguistic issue.

"It is a socio-economic issue," said vice-chairman Huw Lewis.

"The demise of the Welsh language can be seen as a symptom - We respect the values of vibrant communities, be they Welsh-speaking or not," he added.

Although the policy has already been adopted by the national park, it will still be open for scrutiny as it is included in the draft Joint Unitary Development Plan drawn up with Pembrokeshire County Council.

The draft plan is due to be published for public consultation in the spring.