The comments have come from the National Association of Head Teachers (NAHT), which says that removing the exemption is the “right thing to do” but warns that inspection is becoming “an impossible task”.
Currently, outstanding schools are not subject to routine inspection, but instead are regularly risk-assessed. It means that many schools go uninspected for long periods.
The question has come to the fore after the House of Commons Committee of Public Accounts revealed that 1,620 schools had not been inspected for six years or more (as of August 2017).
Furthermore, of 305 outstanding schools that were inspected between September and March this year, only 49 remained outstanding.
Nick Brook, NAHT deputy general secretary, said: “We remain concerned that Ofsted does not have the capacity and capability to deliver the new expectations being placed on them. Resources at the inspectorate are stretched. Inspection is becoming an impossible task. Inspectors are being spread too thinly which results in dubious judgements and unreliable reporting.
“We have argued that Ofsted should focus their limited resources where they can make the greatest impact, that is supporting schools that are struggling to improve, while all other schools should receive a light-touch health check to ensure that they remain good.”
Elsewhere, the DfE also wants Ofsted to include in its reports a rating for financial management and oversight within schools or trusts.
The NAHT said the idea was “extraordinary and misguided”.
Mr Brook said: “The announcement of a new Ofsted rating for financial management and oversight – on the day that the new inspection framework comes into effect – is both extraordinary and misguided.
"Ofsted is incapable of making robust judgements in this area. To do so would require considerable retraining of the inspection workforce and would result in even less time performing their core function – judging the quality of education provided by the school."