The schools inspected had included those pupils identified as giving "cause for concern". It is not necessarily the case that such schools exclude more pupils, however.
An OFSTED spokeswoman said the information from the survey had not yet been analysed. "We think the [national] figure could be more like 7,000, but we don't know."
The most recent Department for Education figures showed that permanent exclusions rose from 2,910 in 1990-91 to 3,833 in 1991-92.
OFSTED's figures also showed that 1,178 pupils in the sample were suspended indefinitely, and 9,699 for fixed periods.
An average of two pupils was expelled from each school, but one in eight schools expelled five or more.
John Fowler, assistant secretary for education at the Association of Metropolitan Authorities, said the figures were worrying. "I hope the Government will work with the local authorities in analysing the data and developing solutions," he said.
While the Government's latest circular says exclusions should be a last resort, he argued, this did not fit with the ethos which had resulted from other Conservative policies, where schools had to fight for survival and look after their own interests.