Police are making another public plea for information a year on from the mysterious disappearance of Christchurch man Michael McGrath.

The 49-year-old builder has not been seen since May 21, 2017, when he left his Halswell home without his car or bike, and with his wallet inside the property.

An initial search for McGrath began in greater Halswell before Police focused in on school friend David Benbow, searching both his home and his mother's.

Mr. Benbow has since sold his home.

Police then conducted a 70-day landfill search in Waipara last June.

Michael's brother, Simon, posted a moving tribute on social media in November, where it seemed he conceded that Michael was no longer alive.