Speaking before the Scottish Parliament’s education committee on Wednesday, Professor Kenneth Muir said there was not a “quick fix” as the SQA, which is due to be scrapped and replaced by summer 2024, is undertaking “two and possible three diets of examinations" in Scotland.
He said the “SQA needs to continue to deliver as well as change” and “take a short, hard look at itself”.
Prof Muir’s comments come after he drew up a report for Scottish education agencies to be replaced and scrapped by 2024.
The report, which ministers have agreed to accept, stated there was too much focus on exams in schools.
It recommends a new qualifications body, potentially named Qualifications Scotland, as well as a replacement for Education Scotland.
Another independent agency is to be established to run school inspections. Legislation will need to be passed at Holyrood to set up all three bodies.
Making 21 recommendations for the future structure of education agencies, Prof Muir said he heard a lot of criticism of the SQA being an “unlistening” and “distant” organisation.
He said: "My report is designed to be a catalyst for further reform and further change.
"It is certainly the case the replacement of SQA and the restructuring of the reform of Education Scotland is a starter, but I think more is needed in order to ensure the education system in Scotland is fit for purpose for current and future learners in what is a very changing world."
Quoting a senior Scottish headteacher, Prof Muir said “for a number of years” SQA had become “tone deaf”.
He said: “In the recent past there have been issues concerning the national qualifications.
"I think it goes back beyond that. I think there was concern expressed that the national qualifications designed to support the curriculum for excellence were not meeting the needs of practitioners and the needs of young people.”
Professor Muir said a “fair degree of discontent” was around how the SQA operates and “the extent to which its governance is representative of some of the expertise that exists within schools”.
Prof Muir said if the new body was adopted as a rebranded SQA, he said himself and the profession would be “very disappointed”.
The professor suggested SQA leadership “needs to look” at the report to use those as “a mirror to reflect on their current practice”.
Prof Muir said: "All of the telescopes need to focus very much on meeting the needs of learners first and foremost.
"In order to do that, we need to put in an infrastructure which supports learning and teaching.”
David Middleton, SQA chair, said the SQA was “surprised and disappointed” by the evidence Kenneth Muir gave, which he said contained “a number of misrepresentations and inaccuracies”.
He said: “We agree with Professor Muir that education reform is needed, with learners at the centre.
"However, the complex functions that SQA carries out on behalf of the Scottish Government are not delivered in isolation.
"They are part of a much wider education system, and change must happen in every part of that system if we are to realise our aspirations.”