The ATO has turned its gaze to online traders, revealing it will launch a data matching program to detect underreporting of income gained from eBay and The Trading Post.

The tax office's program will focus on individuals or businesses who have sold more than $20,000 worth of goods and services through online selling sites in any of the last three financial years.

Tax Commissioner Michael D'Ascenzo urged anyone who has understated their income from the sites to come forward voluntarily.

“If you do so you will be treated fairly and benefit where applicable from significantly lower penalties,” he said.

During the sweep, records will be matched against different identifiers such as tax file numbers, ABN’s, addresses and date of births.

The accused will be given the opportunity to confirm or contradict the information gleamed from the program, and the information is being collected in accordance with privacy commission guidelines, D'Ascenzo said.