Secrétaire parlementaire
Colbeck was appointed Parliamentary Secretary to the Minister for Agriculture, Fisheries and Forestry in October 2004. In January 2006 he was appointed Parliamentary Secretary to the Minister for Finance and Administration. With the defeat of the government led by John Howard in 2007, he was appointed to the shadow ministry as Shadow Parliamentary Secretary for Health. He was shifted to the role of Shadow Parliamentary Secretary for Agriculture, Fisheries and Forestry in September 2008. In September 2010, Colbeck was appointed Shadow Parliamentary Secretary for Fisheries and Forestry and Shadow Parliamentary Secretary for Innovation, Industry and Science by the new opposition leader Tony Abbott. Abbott nominated Colbeck for appointment to the Abbott Ministry as the Parliamentary Secretary to the Minister for Agriculture following the 2013 federal election.