Joseph is leaving the Super Rugby champions at the end of the season to take over as head coach of Japan and Plumtree was linked with the job earlier this week.
"There has been some speculation about my coaching future over the past week, but my family consider Wellington to be our home and the Hurricanes are a team that is close to my heart," Plumtree said in a statement on Wednesday.
"We have a great group of players and coaches at the Hurricanes and I'm glad to have the opportunity to continue working with them over the coming seasons."
Plumtree has pedigree as a head coach having led the Wellington provincial side from 2003-06 before he moved to South Africa where he coached the Sharks in Super Rugby from 2008-13.
He quit as Ireland forwards coach to return to New Zealand to link up again with former assistant Chris Boyd, who was appointed to the Hurricanes head coaching role in 2014.
Hurricanes Chairman Brian Roche welcomed the news.
"We were thrilled when John decided to return home from Ireland with his family to join the Hurricanes in 2015 and we are just as thrilled that he will stay with us for another two years," Roche said.
"We see him as an integral part of the Hurricanes future and a key part of our succession planning."
(Reporting by Greg Stutchbury; Editing by Peter Rutherford)
