The 6-9% rise in house prices in Wales is sustainable

John Mitchell, chief executive Principality Building Society

These areas include Newport, Bridgend, Powys and Pembrokeshire, while in Monmouth even a couple on average wages will struggle to buy a house.

The home-buying survey analysed whether local house prices were more or less than three times the average working wage of a single person.

Areas where average prices are less than three times the average wage include Blaenau Gwent, Neath Port Talbot and Torfaen.

The research looked at workers in a range of essential occupations including nursery nurses, local government workers, teachers and other frontline public services.

'Catch up'

Figures showed that in some areas, even the joint earnings of a couple only amount to very limited options.

John Mitchell, chief executive of the Principality Building Society, said Wales had been experiencing a "catch up" on house prices with other more affluent regions.

"House prices are controlled by economics at the end of the day; people will buy what they can afford," he said.

Mr Mitchell added that low mortgage lending rates meant that the recent phenomenon of buy-to-let mortgages - which has kept the housing market buoyant in some areas - could possibly level out.

"With mortgage rates having fallen so dramatically, it is more expensive to rent than to buy," Mr Mitchell explained.

The purchase of second homes remains a thorny issue in parts of rural Wales, where Welsh language campaigners have urged house prices to be "capped" to allow local people to buy.

Hotspots

Mr Mitchell added: "We have a sustainable market now, we do not want a boom and bust situation.

"The 6-9% rise in house prices in Wales is sustainable, but I think there will possibly be an interest rate rise in the next 12 months."

In August, Land Registry figures showed that house prices in Wales had risen by 6.5% for the year to July, compared with 11% in England.

In Wales, the average cost of a house had risen from £64,767 to £68,963, with hotspots in Cardiff and Monmouthshire.

But in Blaenau Gwent, house prices are the cheapest in England and Wales, at an average of £35,000.

In London, a detached property costs more than £400,000 to buy.