An affected stretch of Glyndwr's Way

The 4x4 drivers have been accused of churning up a mile-long stretch of Glyndwr's Way in Powys.

Wardens say some people even travel from Germany and the Netherlands, but constant use is eroding the track.

Powys Council has issued an emergency closure order for the section near Llanbadarn Fynydd.

Drivers are allowed to use the section of 135 mile-long byway, but frequent use by 4x4 vehicles is causing problems.

The increased usage of 4x4 vehicles is causing a problem Head warden Rab Jones

Another three-mile section of the byway, just off the national trail, has been closed to vehicles too.

Notices have been put in the area to warn drivers and barriers have also been erected.

Many 4x4 vehicles use the trail, also used by walkers and cyclists, throughout the year driving off-road in sometimes slippery conditions.

Head warden of Powys County Council's countryside services, Rab Jones, said: ""We don't know how people learn about the trail, but we think there may be an website they use.

"We have been forced to issue an emergency closure order on all vehicles on a section because it's become so muddy."

Glyndwr's Way is one of only three national trails in Wales, the others being Offa's Dyke and the Pembrokeshire Coast Path.

Mr Jones added that it was "business as usual" for walkers and cyclists.

Countryside warden for Radnorshire, Carlton Parry, said he was told about the problem last month by a landowner.

'Damaging wildlife'

"I understand convoys of up to 12 (4x4s) at a time have been seen," he said.

Notices have been put up and in some areas barriers have been erected.

Opened in April 2002, Glyndwr's Way starts on the Powys/Shropshire border at Knighton and ends in Welshpool.

The trail takes visitors past a number of sites associated with Welsh Prince Owain Glyndwr who fought English forces in the 15th Century.

Meanwhile, the Council for National Parks has called for a crackdown on motorbikes, four wheel drives and other off-road vehicles on rights of way.

It follows a CNP survey of all park authorities in Wales and England.