"Bro I think of you out there somewhere and I am sitting here without a clue. I hope that you return to me someday.
"For as long as I live my thoughts will be always with you."
McGrath's disappearance has been described by family as out of character and police have been investigating people and properties of interest.
Detective Inspector Darryl Sweeney said the investigation was continuing, with an increased presence in the Halswell area today.
"Michael has been missing for nearly two weeks and police have grave concerns for his well-being.
"Police will be going door to door in and around Checketts Ave to establish movements and sightings of Michael."
A leaflet drop of the special notice that was released yesterday outlining the details of the information police are seeking would also be completed in the area, Sweeney said.
Police tomorrow planned to begin again the search phase around the greater Halswell area.
People of interest and witnesses also continue to be interviewed, but he could not yet share further details on this.
The scene examination was also continuing at a Candy's Rd property, as well as the examination of relevant vehicles.
McGrath is described as around 184cm tall, of slight, fit build and with brown/grey hair.
Anyone who has information about McGrath or has employed him in the past few weeks is asked to call Christchurch police on (03) 363 7400 and cite file number 170523/6008.
Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.
