A teenage computer hacker who caused millions of dollars of damage as part of a global cyber-crime ring has been hired by a New Zealand telecommunications company to provide security advice. Owen Thor Walker was discharged without conviction as an 18-year-old last year after admitting six cyber-crime charges.

He was the alleged brains behind a group of international hackers who used his programs to access personal data, send viruses around the world and commit other crimes, causing losses of 20 million US dollars, police said last year.

Walker -- who went under the online name of "Akill" -- designed an encrypted virus that was undetectable by anti-virus software, they said. He is now providing security advice for TelstraClear, the New Zealand arm of Australia's largest telecoms firm Telstra.

TelstraClear communications manager Chris Mirams said Walker had advised major clients about security threats. "He was able to give advice on how to mitigate the risks and what makes them (cyber criminals) tick, what motivates them," Mirams told Radio New Zealand Wednesday. "He really wants to put his information, his unique insight, to the good for New Zealand businesses." Walker is under contract to Telstra until late this year, he added.