The Turnbull government will strip back highest-level protections in a host of sensitive marine areas, including critical waters near the Great Barrier Reef, saying it is protecting the environment while supporting fishing and tourism.

But Labor has branded the changes “the largest removal of areas from conservation in history” and will seek to disallow the proposed regulation in Parliament.

The government is on Wednesday expected to table the proposal, which is a culmination of a review that began in 2014 under former Prime Minister Tony Abbott.

Mr Abbott suspended the unfinished marine protection process instigated by the former Labor government, which would have created 40 additional reserves along the Australian coast.

The Coalition changes, which would be in place for a decade, retain 3.3 million square kilometres of Australia's protected offshore regions but allow commercial fishing and other activities in a range of new areas.