Isaac Joseph is a Papua New Guinea politician. He has been a New Generation Party member of the National Parliament of Papua New Guinea since July 2007, representing the electorate of Mendi Open.Joseph was a church pastor before entering politics. He was elected to the open seat vacated by Michael Nali, who made an unsuccessful attempt to shift to the Southern Highlands Regional seat. He was subsequently appointed Shadow Minister for the Public Service by Opposition Leader Sir Mekere Morauta. He has been critical of past neglect within the Mendi area, and has pledged to push for a number of reforms, including new development initiatives, reform of the public service, improved enforcement of law and order and an end to tribal fighting.