The Tax Office has been criticised for spending millions of dollars on desktop-based software for Macs instead of launching a web-based version that would allow taxpayers to file their tax return on any computing device.

The development of e-tax for the Mac platform is also being criticised for porting the Windows version's design and feel — as well as most of its code — to the Mac.

Glitches in the Mac version are also being reported in web forums, like Whirlpool, by users. Mac users have also contacted Fairfax Media to report problems, one of which causes the app to crash.

Usability expert Stephen Collins, of Canberra design firm Acidlabs, said the porting of the app would ''cause user discomfort''. He downloaded it and described it as ''a jarring experience''.

''It looks and feels like a rushed job and it feels like it's been done lazily,'' he said. ''They haven't put in the effort that you would expect. If they are going to do this, and it's taken however many years, you'd expect them to put in a real effort to do adequate testing on a real user base and to have resolved those problems before release. Post release they are going to cost a lot to fix.''