Anderson debuted for
New Zealand Warriors in Round 17 of the
2002 National Rugby League, playing against
Cronulla at
Toyota Park on 7 July 2002. That year the New Zealand went on to the
2002 NRL Grand Final, which they lost 30–8 to the
Sydney Roosters. In 2003 he played as New Zealand Warriors fell one victory short of a consecutive Grand Final appearance. At the end of 2003 Anderson made his International début for
New Zealand national rugby league team in the 100th match between the New Zealand and the
Australian team. His brother,
Louis, also made his debut in the same match. Playing as a , Anderson scored two tries as the Kiwis won 30–16. Anderson also played for the
2004 New Zealand Tri-Nations side. The campaign was unsuccessful although he did manage to score tries in all but one of the 4 test matches against Australia and Great Britain. The tour also saw the start of brother Louis Anderson's Test career. Before departing at the start of the 2005 NRL season for the Super League, Anderson had carved a reputation for tough tackling and good ball skills. ==St Helens==