The art gallery and museum is currently closed to undergo extensive repairs and structural changes. A tender seeking contractors for the project was issued only this week.

John Meunier, who helped create the landmark building more than 30 years ago, said he was concerned about changes to the main entrance and the Hutton Rooms.

Architects John McAslan + Partners won the commission to carry out the work last year.

In a letter to the architects, Mr Meunier, emeritus professor of architecture at Arizona State University, said: “The issue for me is the long term and whether it retains its status as one of the best 20th century works of architecture in Scotland, superbly matching the architecture to the works of art, while continuing to honour the intentions of its progenitor .

“For it to do that a lot more has to be retained, including the extended entry sequence of graduated spaces, and the programmatic requirement of the will that the restored Hutton Rooms be retained.”

Paddy Pugh, director of conservation and planning at architects McAslan, wrote to Mr Meunier: “We have the utmost respect for the building and have, as you know, taken a great deal of care to understand its design intent and significance.

“There is no doubt in our minds that The Burrell fully deserves its recognition and status as a Category A listed building.”

Glasgow Life said it had not been contacted by Mr Meunier. It said the “original, existing entrance will remain exactly the same, open and in use at all times”.

A statement added: “The new scheme will create an additional entrance to improve access into and around the museum.

“Access, although important when the Burrell was designed in the 1970s, no longer meets visitor expectations or standards required for a major cultural building.

“The scheme will also repair and re-service the building so that its internal environment is once again, appropriate for displaying a nationally important collection.”