The Berejiklian government's overhaul of the Planning Act marks a "missed opportunity" to promote greater community input and address the long-term threat from climate change, environment groups say.

The new Act - expected to be voted on in the Legislative Council overnight Tuesday and to pass the lower house on Wednesday - includes the renaming of the Planning Assessment Commission to become the Independent Planning Commission and new community participation plans.

Picking winners: overhaul of NSW planning laws likely to fall short for those wanting more public rights to challenge verdicts. Credit:Vincent Mundy

Pending last-minute amendments, though, the new IPC will no longer have a midway review function in assessing major projects.

Nor will it restore third-party merit appeals if a public hearing is held, "a major flaw" in the current process, the NSW Environment Defenders Office said, noting communities near 30 large projects had already been unable to challenge their merits in the courts.