Sydney Airport has dropped its iPhone and Android apps which let passengers track their domestic and international flights, including keeping an eye on changes to departure gates and delays to boarding.

The apps are no longer available from the respective platform's app stores, and a spokesperson for Sydney Airport confirmed that both have been withdrawn from the market.

A change in usage from when the apps were launched in 2011 (on the iPhone) and 2013 (for Android) is understood to have led to the airport's decision to no longer develop or support the smartphone software.

Sydney Airport says that passengers are now making more use of alternative channels such as the airport's mobile-friendly website along with each airline's own apps.

Flight information is also available at sydneyairport.com.au/flights and via automated services on Twitter and Facebook, with notifications served by tweeting a flight number to @flySYD or sending a Facebook message with the flight number to the @flySYD Facebook page.