POLICE have launched a large-scale land and water search west of Lawrence as they continue their investigation into the disappearance of Grafton woman Sharon Edwards last year.

Strike Force Burrow detectives, operational support group officers and police divers arrived at an expansive dam, which is kilometres away from any main roads, about 10am and have set up a command post nearby.

While The Daily Examiner was on scene, divers worked through the reeds and lilypads on the fringes of the dam while a cadaver dog rummaged its way along the water's edge.

In the distance operational support officers performed a line search of the bushland on foot.

It is understood a number of bodies of water in the region will be examined during the search, which could continue for days.

Mrs Edwards, a grandmother and beloved school teacher at Coutts Crossing Public School, has now been missing for sixteen months, and is presumed by police to have been murdered.