Sydney's Darling Harbour has become the first Australian site nominated for a heritage alert list compiled by an international body that observes threatened sites and monuments.

The International Council on Monuments and Sites is considering the nomination, which is aimed at saving the precinct from a planned $2.5 billion remake, Fairfax Media reports.

It's the first time an Australian site has been nominated for such an alert.

The move comes amid plans by NSW Premier Barry O'Farrell to overhaul the popular harbourside area.

If accepted, the nomination by the Australian chapter of the international conservation group Docomomo would put Darling Harbour on the same heritage alert list as historic Melnikov House in Moscow.

This site is threatened by nearby development and President Vladimir Putin has been urged to step in to save it.