A report by the party's rural housing taskforce recommends changes in planning law to protect Welsh-speaking areas.

Published on Tuesday, the report says land should be allocated for affordable local housing, calls for grants for locals to buy houses and recommends council tax on holiday homes should double.

The party's housing plans came under fire in February when Gwynedd Councillor Seimon Glyn said action should be taken to stop the effect of English migration into Welsh-speaking villages in north Wales.

"It is is no use to the community to have retired people from England coming down here to live and being a drain on our resources," Mr Glyn said.

"Once you have more than 50% of anybody living in a community that speaks a foreign language, then you lose your indigenous tongue almost immediately."

The Plaid Rural Taskforce Chairman Dafydd Wigley AM said the proposals should be implemented within a year to save the "crisis" in rural Wales.

But the plan has drawn criticism from the Liberal Democrats.

Party housing spokesman Peter Black AM saidMr Black said the plan pandered to nationalists who wanted to keep out incomers.

"I do not believe that we can frame our planning laws around the Welsh language," he said.

"Nor can we take punitive measures against second home owners in the way that they propose as these will have an impact on the value of the homes of local people."

He said the coalition assembly was making 140 low-cost homes available to local people in their own communities through the Homebuy scheme this year.

Under fire

The Welsh Language Society welcomed Plaid's proposals but said they did not go far enough because the plan did not control private sector housing.

Unveiling the report on Tuesday morning, Mr Wigley said: "I would be looking for these plans to be implemented in the next 12 months.

"The crisis that we have got for housing in rural Wales is such that it demands action now.

"Given that we have proposals here that are acceptable to any government that is concerned with social justice, the action should take place during this coming year."