A top housing officer has warned that Scottish councils will be severely stretched by new regulations on homelessness pushed through last week.

Under the Homelessness (Scotland) Act 2003, councils will be prevented from housing families with children or pregnant women in bed and breakfast for more than 14 days. But Mark Turley, director of housing at Edinburgh Council, said the immediate introduction of the rule would lead to the neglect of other vulnerable client groups.

A motion to defer its introduction was rejected by the Scottish executive's communities committee.

Turley is so disappointed that he and two other officers have stepped down from the executive's homeless monitoring group. They and the Convention of Scottish Local Authorities thought the plans should have been postponed until April, giving councils longer to prepare.

"Councils are not ready as there hasn't been adequate preparation," Turley said. "Instead of taking a strategic and planned approach to implementing this, councils will be forced to chase around ensuring they comply with it. We will be spending a disproportionate amount of time implementing this policy."

He said the decision threatened the understanding between councils and the executive over Scotland's long-term approach to homelessness.

Cosla president Pat Waters said the legislation would not reduce the overall number of people living in B&Bs and divert attention away from "real homeless needs".

The legislation places new definitions on the type of accommodation homeless families should be offered. B&Bs would be used in "emergency or exceptional circumstances" only.

Homelessness charity Shelter Scotland welcomed the change, adding that half of all Scottish local authorities had already stopped using B&Bs.