Styris made his debut for New Zealand in a One Day International at Rajkot in 1999/2000. His maiden wicket was that of Sachin Tendulkar, one of 3 wickets for the match.

He had to wait until mid 2002 to play his first Test Match, against the West Indies at Grenada. His debut had almost come at Karachi 2 months earlier but the match was abandoned due to bomb blasts near the team hotel. In the Test at Grenada he batted at number 8 and top scored with 107. When it was New Zealand's time to bowl Styris came on and took 2 for 88. The first of his wickets was that of Brian Lara which gave him impressive maiden scalps in both formats of the game. He made an unbeaten 69 in the second innings to complete a dream debut but missed out on the man of the match award which went to Chris Gayle who scored a double hundred.

In the ODI series after the Tests he continued his form but this time with the ball, taking 6 for 25 at Trinidad. This broke the record for best One Day International bowling figures by a New Zealander.