Teachers are to come under increased scrutiny from Ofsted, with inspectors spending more time in class observing lessons.

Changes to the inspection framework, due to be introduced in September 2009, will lead to a significant toughening up of Ofsted’s light touch regime. The changes follow criticisms that reduced tariff inspections for the top 30 per cent of schools resulted in too few lesson observations and put too much pressure on teachers to evaluate their own performance.

Concerns were raised by the Commons children, schools and families committee that a cut in the number of classroom observations could lead to inspectors failing to recognise problems in schools. But Christine Gilbert, the chief inspector, told the committee this week that this was being addressed.

“We are unique in having the power to enter schools and classrooms and I can assure you that any new arrangements will make the most of this,” she said.

“This means that inspectors may spend more time in the classrooms, inspecting the quality of teaching and the impact it is having on the quality of lessons and children’s learning. It will also mean that we are able to gather information about how well certain subjects are being taught.”

The increased hours of observation are likely to be introduced following trials and consultation. The amount of time dedicated to watching lessons will depend on how schools are performing.

Ms Gilbert’s comments come before a major consultation on the review of the inspection regime is launched on Monday. It is expected to recommend that high-performing schools are only inspected once every six years, instead of every three years. Weaker schools could be inspected at least once a year.

However, the consultation will not include controversial proposals to assess schools on a range of pupil wellbeing indicators. These will be consulted on separately from July.

Ms Gilbert also told the committee that parents should be given more say over when schools are inspected. Their opinions should be taken into account.

John Dunford, general secretary of the Association of School and College Leaders, said schools had found recent inspections “unsatisfactorily brief” and too focused on leadership rather than classroom teaching. “This will help redress the balance,” he said.

Teachers can respond to the consultation from Monday at www.ofsted.gov.uk.