He can leave his parents believing the filter is still working.

His method ensures the software's toolbar icon is not deleted.

Tom, a former cyber bullying victim, fears a computer-savvy child could put the bypass on the internet for others to use.

"It's a horrible waste of money," he said. "They could get a much better filter for a few million dollars made here rather than paying overseas companies for an ineffective one."

Communications Minister Helen Coonan said the government had anticipated children would find ways to get around the NetAlert filters.