Transport for NSW (TfNSW) has scrambled to respond to a mistake that saw it ship out a dev tool to users’ Android devices.

Users reported seeing an app called Leaks - or LeakCanary - on their Android devices early last week after they downloaded TfNSW’s previous update to the Opal Travel app.

LeakCanary is an open source “memory leak detection library” that app developers use to identify memory leaks and reduce crashes.

Users say the app was installed on their smartphone as a “dev extension for Opal Travel”.

When users uninstalled Leaks, the Opal Travel app disappeared from their devices as well.

Four days later, TfNSW released an updated version of its app to fix the problem.

“The Android version was released with some developer code meant for internal purposes,” a spokesperson said.

“Some of our Android customers have reported seeing what appears to be an additional app called ‘LeakCanary or Leaks’ on their phone.

“We apologise for any confusion caused. An updated version of the app is now available which will remove Leaks or Leak Canary.”