Since making his senior side national team debut in 2001, Dwyer has played over 250 matches for Australia and scored over 150 goals. In 2001, he earned a silver medal in the Champions Trophy competition. In 2002, he won a silver medal at the World Cup. That year, he also won a gold medal at the 2002 Commonwealth Games. His team finished fifth at the 2002 Champions Trophy tournament. In 2003, his team finished second in the Champions Trophy competition. He injured himself in the tournament when he tore the anterior cruciate ligament in his left knee. Going into the Athens Olympics, he was recovering from a knee injury. He is famous for scoring an extra time goal in the final of the 2004 Olympics, which resulted in Australia winning the gold medal and being the best player in the world. In 2005, he earned a gold medal at the Champions Trophy competition. In 2006, he won a silver medal at the World Cup. His team finished fourth at the 2006 Champions Trophy tournament. He also won a gold medal at the 2006 Commonwealth Games. By March 2006, he had 122 caps and 79 goals for Australia. In 2007, his team finished second in the Champions Trophy. In December 2007, he was a member of the Kookaburras squad that competed in the Dutch series in Canberra. In 2008, his team finished first in the Champions Trophy competition. He won a bronze medal at the 2008 Summer Olympics. He was carried off the pitch with a hip injury in the middle of the game against Canada that Australia won 6–1. New national team coach Ric Charlesworth named him, a returning member, alongside fourteen total new players who had fewer than 10 national team caps to the squad before in April 2009 in a bid to ready the team for the 2010 Commonwealth Games. In 2009, he participated in two test matched against Spain in Perth in the lead up to the Champions Trophy. In 2009, he won a gold medal at the Men's Hockey Champions Trophy competition. He was a member of the national team in 2010. That year, he was a member of the team that finished first at the Hockey Champions Trophy. In 2010, he also represented Australia at the Commonwealth Games, and played in the game against Pakistan during the group stage. In the gold medal match against India that Australia won 8–0, he captained the side and scored a goal. He also won a gold medal at the World Cup and the Champions Trophy in 2010. While at the 2010 World Cup, the Indian hosts provided extensive security for him and other hockey competitors. The Sydney Morning Herald said he said it was the tightest security he had ever seen as a competitor in an international competition. He did not compete at the Azlan Shah Cup in Malaysia in May 2011 because he was injured. In December 2011, he was named as one of twenty-eight players to be on the 2012 Summer Olympics Australian men's national training squad. This squad will be narrowed in June 2012. He trained with the team from 18 January to mid-March in Perth, Western Australia. In February during the training camp, he played in a four nations test series with the teams being the Kookaburras, Australia A squad, the Netherlands and Argentina. He played for the Kookoaburras against Argentina in the second game of the series where his team won 3–1. He had a short break from training following the test series. He is one of several Queensland based players likely to play in a three-game test series to be played in Cairns, Queensland from 22 to 25 June against the New Zealand Black Sticks. Final Olympic section will occur several days before this test and his inclusion in the series will be contingent upon being selected. Dwyer does not play for the National team anymore.
