It found that the core national curriculum subjects, science, maths and English, have been hardest hit.
Eight local education authorities of the 70 responding reported they had no advisory posts left, while others told of gaps in their service.
The number of specialist subject advisers fell by about a third in the two years between 1992-93 and 1994-95, the report says, and the number of inspectionadvisory posts fell by a quarter. The Royal Society says it does not believe that any other arrangements are being made to compensate for the loss of local authority services.
Sir Roy Harding, deputy chairman of the Royal Society's education committee, warned that the loss of support could lead to a drop in standards of education.
The poll, carried out by the National Foundation for Educational Research's education management information exchange, found that the number of science advisory teachers fell by 46 per cent in the past two years, while 43 per cent of maths advisers and 41 per cent of English advisers were lost.