Incremental change to the emissions trading scheme is inevitable, climate change minister Tim Groser says.

A fairly cryptic release of the government's review of the emissions trading scheme has one little pearler in it: farming will stay out of the ETS until 2018. At least.

The government is signalling a move against the widespread purchase by major carbon emitters of cheap international carbon credits rather than using New Zealand-based units derived from activity that either offsets or reduces total carbon emissions.

Important progress has been made on work towards a single economic market between New Zealand and Australia, Finance Minister Bill English said this morning, following a meeting with his Australian counterpart, Treasurer Wayne Swan.