LONDON (Reuters) - Pop star Madonna has challenged hikers who want to walk across her $16 million English country estate.

The case pits the rights of landowners to keep their domains private, against a large and determined band of English walkers who demand full access to the countryside.

A public inquiry, which opened on Wednesday into the dispute at the 1,200 acre Ashcombe House estate which the singer owns with her British film director husband Guy Ritchie, is expected to last five days, with a verdict due in the Summer.

The couple are appealing against a government Countryside Agency decision which defined 100 acres of their land in Dorset, southwest England, as open country and therefore open to the public.

Madonna and Ritchie claim the land should be reclassified as "semi-improved" grassland because it is used for shooting game. This would define it as agricultural land and exclude it from public access.

British media have also quoted the couple as insisting their right to privacy must be considered, as they seek to deter celebrity watchers and paparazzi from wandering on their land.

The hikers sense a win. "We are confident that we are right and the land should stay on the map," Andy Wistow, a senior Countryside Officer, told Reuters.

The dispute is the latest to hit the couple since they bought the house. They have already complained about low-flying aircraft and were ordered to remove new high security gates after failing to apply for planning permission.

Madonna's fight is one of several currently being fought between landowners and hikers -- "ramblers" as they are known in Britain.

The Ramblers Association describes gaining access to open country as a benefit to the whole nation and one Times newspaper editorial advised Madonna and Ritchie that they should not be feared.

"Ramblers are unworldly types who will -- unthinkable as it seems -- probably never have heard of her, being far more concerned with their maps in little waterproof covers, their flasks of sweet tea and cling-filmed picnics of cheese sandwiches and fruit cake," it said.

Madonna has not always enjoyed the backing of the English press since she married Ritchie, with a columnist for the tabloid Daily Mail offering a particularly trenchant opinion following reports she was considering moving back to the United States.