SYDNEY Airport Corporation quietly increased the noise projections that underpinned its new master plan shortly after the public consultation period for the plan had closed, it has been revealed.

This year the corporation received approval for a substantial redevelopment of Kingsford Smith Airport, including the expansion of the international and domestic terminals.

It has now emerged that the maps of Sydney provided to the public showing which areas of the city would be affected by exposure to aircraft noise over the next 20 years were based on poor modelling and had to be changed.

Scores of homes in Hunters Hill, Rosebery and Lilyfield that had been outside the noise footprint were now within it, while dozens of others in Leichhardt, Petersham and Stanmore moved from moderate to heavy noise zones.

These homes would not only experience noise, but also the restrictions on development that come with being in a designated aircraft noise zone.