The federal government's much-publicised COVIDSafe app has been criticised as a waste of time and money having only picked up 17 positive contacts, all in NSW, since its launch in late April, at a cost of close to $12 million.

Department of Health representatives told Senate Estimates in Canberra yesterday that the full cost of advertising the app was $6.95 million, with an extra $5m spent on developing it and subsequently improving functionality.