Detectives believe that at least one body is buried in Letterbox Field at Kempley, Gloucestershire, a mile from the village of Much Marcle. Neither Mr West's first wife, Catherine, nor his daughter, Charmaine, have been traced, despite massive publicity.
Yesterday's dig, shielded from the gaze of press and public by two tents, was the first time that detectives had carried out excavations away from Mr West's home at 25 Cromwell Street, Gloucester, where the remains of nine young women have been found.
Detective Superintendent John Bennett said: 'This search will continue for perhaps two or three days and may be longer.' He also revealed that the operation might later move to another site. Ten members of a specialist police team are digging three to four feet down into the soil, which has already been scanned with the ground-penetrating radar device that located human remains at the house in Cromwell Street.
Hilary Allison, spokeswoman for Gloucestershire Police, said officers were treating the search for bodies in the field 'like an archaeological dig'. She added: 'We are using a mechanical digger as well as digging by hand. We are going over the area very carefully.'
Mr West, 52, a builder, is in custody charged with murdering nine women over a 21-year period, including his daughter Heather, 16, who vanished seven years ago. He is due to appear in court again next month.
The owners of the field being excavated yesterday denied cashing in on the investigation by charging journalists pounds 50 a day for car parking and selling them hot snacks at pounds 2 each.
Reg and Juliet Watkins, who run a 500-acre farm which includes the field, have set up a mobile snack bar called 'The Dig Inn'. Some of the takings will go to school playgroups in neighbouring villages.