Cushman and Wakefield planning and environment partner Michael Crook said many councils have delayed carrying out this task due to a widespread belief that the government would go ahead with its scheme for a planning gain supplement.
"Local authorities that have not got to grips with this will have to do so rapidly," he said. "They need a sound basis on which to seek contributions for infrastructure from developers."
Councils who have not got guidance documents in place will still be able to negotiate contributions but they may have difficulty if they have to go to appeal, he added.
In the south, about 70 per cent of local authorities do not have an SPD on planning obligations. In the north the figure is as high as 80 per cent, Crook estimated. It takes about nine months to draw up an SPD so councils should start as soon as possible, he advised.
The firm runs a planning obligations service with local government finance specialists Sector Treasury to carry out health checks on councils' section 106 processes.
It is working on such an assessment for Bath and North East Somerset Council, among others.
Last month, the government announced that it is dropping its controversial proposal for a planning gain levy (Planning, 12 October, p1). A tariff system modelled on that used in Milton Keynes will be brought forward in the reform bill.