A teenage hacker who was part of an international gang who stole $20m from bank accounts has avoided jail, because police want to use his hacking skills.

New Zealander Owen Thor Walker has been fined $10,000 and told to hand over his IT equipment.

Walker had been paid for software designed to access usernames, passwords and credit card details.

Walker admitted charges of accessing a computer for dishonest purposes, interfering with computer systems, possession of software for committing crime and accessing computer systems without authorisation, the New Zealand Press Association said.

Investigators said the program written by Walker was one of the most advanced they had ever seen.