The long-awaited reforms, in effect from Saturday, replace the Part 3A system, which allowed the former Labor government to override local councils and approve projects deemed to be of ‘‘state significance’’.

Under the changes, a new Part 4 of the planning laws will deal with private state-significant developments. Public state significant infrastructure will be dealt with by a new Part 5.

The monetary thresholds will vary with the class of development.

The new State Environmental Planning Policy will approximately halve the number of proposals dealt with by the government.

Environmental Defender’s Office principal solicitor Kirsty Ruddock said the changes were mostly welcome.

‘‘It’s definitely an improvement,’’ she said.

‘‘There are more checks and balances and not as many ways for developers to jump the hurdles.’’

Under the changes, the Planning Minister can call in state significant development projects only if advice is obtained and made publicly available from the Planning Assessment Commission on the state or regional significance of the project.

Ms Ruddock said the changes should prevent a repeat of the circumstances that led to state government approval of the proposed Catherine Hill Bay and Huntlee developments.

‘‘The residential component should come out of it [Part 4 application].

‘‘If they want to make a residential project and do a spot rezoning they have to go through the Planning Assessment Commission and convince them it should be a state-significant site.’’

Ms Ruddock said she was wary of the commission’s autonomy.

‘‘The problem with the [Planning Assessment Commission] is that the people are still nominated by the minister. How much of a check and balance is that?’’

A Department of Planning spokesman said the commission could not be compromised: ‘‘The Planning Assessment Commission is an independent body of experts.’’