Off-road motorists are taking down protective fences to ride roughshod over Aboriginal middens, Tasmanian Greens senator Peter Whish-Wilson says.

Senator Whish-Wilson said some motorists were not just continuing to flout the law by using banned tracks in the 100,000-hectare Arthur Pieman Conservation Area, they were joyriding over middens protected by fences and signs.

The Greens senator flew over the area on Tasmania's north-west coast looking for evidence of illegal access to banned tracks.

While he saw no vehicles during the flyover, he found fresh tracks.

"We saw evidence of continued damage to both the tracks leading into the Sandy Cape area," Senator Whish-Wilson said.

"And we saw what looked like deliberate vandalism of areas of cultural significance to the Aboriginal community that had been fenced off.

"The fences are there to prevent anyone from accessing specifically the dunes at Ordinance Bay, which is the largest midden site in the world, and those fences have been ripped down.

"The entire midden site has been criss-crossed with four-wheel-drive tracks."

The ABC has previously reported on four-wheel-drive and quad-bike users openly defying a legal ban on using the tracks.

The Hodgman Government's bid to upgrade and reopen the tracks was halted after the Tasmanian Aboriginal Centre lodged Federal Court appeal and won an interim injunction.

The case is due to be heard in August but a ban on using the tracks has stood until a court decision rules otherwise.

Four-wheel-drive advocates alarmed at inaction

Sorry, this video has expired Track bans continue to be ignored, says Senator ( Michael Atkin )

Senator Whish-Wilson, who was accompanied by Jarrod Edwards from the Tasmanian Aboriginal Centre, claimed the Tasmanian Government was ignoring the problem.

"While Will Hodgman turns a blind eye to policing this area, while no people are being fined for this kind of transgression, we essentially have state-sponsored vandalism of our precious cultural heritage in Tasmania," he said.

The Premier vowed to crack down on law breakers.

"We are determined to stamp out any incidents of criminal activity or behaviour that does not conform with community expectations and this is one of those," Will Hodgman said.

Four-wheel-drive advocates were alarmed by what they claimed was a lack of action against the offenders.

Brian Hevey of 4WDTasmania said complaints had been made to the department of Parks and Wildlife as far back as February but no one had been prosecuted.

"You'd like to think that the legal system steps up and people are prosecuted if they do the wrong thing," he said.

Opposition Leader Bryan Green said government indifference and cuts to Parks funding meant little could be done to prevent the illegal behaviour.

"The Government is either not listening or is so hell bent on slashing the public service that they are not in a position to actually do anything about it," he said.

In a statement, the Department of Parks and Wildlife said it was continuing to investigate earlier incidents and charges could be laid.

"There are currently 11 persons of interest identified in relation to possible offences which could result in either court action or infringement notices," the statement read.

"The appropriate course of action will be taken once investigations are finalised."