Federal Environment Minister Sussan Ley has rejected a push by the environmentalist Bob Foundation for the large North-West and West Coast area in Tasmania to be listed.

Situated in Tasmania's north-west, the Tarkine Forest Reserve is a huge area of temperate rainforest, sand dunes and coastal heathland with strong links to the Tasmanian Aboriginal people.

Foundation campaigner Scott Jordan said Ms Ley's reply was to the effect she believed the Tarkine was sufficiently protected at this time.

"(That) of course makes her the sixth (successive Environment) Minister to ignore Australian Heritage Council advice (from 2012) it should be national heritage listed," Mr Jordan said.

Comment was sought from Ms Ley.

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The Bob Brown Foundation renewed the push for national heritage listing in recent times as tensions flared over miner MMG's proposed tailings dam at South Marionoak, which will be assessed under federal environmental law following a decision by Ms Ley.

MMG says the mine will be forced to close by 2024 if a new tailings storage solution is not found.

It said the mine supported 500 jobs.

"We have sought expert advice, conducted risk assessments and progressed the options that were deemed to offer the most balanced solution in terms of social and environmental impact," it said.

"To date, the site that offers this is South Marionoak."

The Bob Brown Foundation's protests slowed preparatory work at South Marionoak.

MMG later paused the work following a legal letter from the foundation.

The foundation suggested a range of alternatives. MMG rejected them, saying they were not safe.

The company's nominated alternative site at Natone Creek would also be opposed by the foundation.

Mr Jordan said national heritage listing did not rule anything out, but meant that as well as the usual environmental assessments, effects upon heritage values would be considered, essentially raising the bar.

"We have miners and loggers lined up saying their projects meet the highest standards, so why not have the highest environmental standard apply?" he said.

Labor's environment minister in 2013, Tony Burke, rejected the push for national heritage listing of the Tarkine, although he did list a relatively small amount of coastal land to protect Aboriginal heritage sites.