There's been an upheaval at Canada's National Gallery in Ottawa with the abrupt departure of chief curator David Franklin.

Staff were informed in a terse e-mail on Thursday from gallery director Pierre Théberge that Franklin "is currently on leave," according to a report in the Ottawa Citizen.

No reason was given, nor was there any return date.National Gallery of Canada director Pierre Théberge, pictured here in June, said chief curator David Franklin is 'on leave' but gave no return date. (CBC)

The report also said employees were shocked by Franklin's departure, expressing the belief that they did not expect him to return.

Franklin's exit throws two major exhibitions into turmoil.

An internationally renowned expert on Italian Renaissance art, Franklin had been co-ordinating the gallery's main summer exhibit for 2009 of Italian Renaissance and Baroque art. He was also the curator of the Caravaggio exhibit slated for 2011 or 2012.

Massive exhibits of this kind are years in the making, requiring international contacts and expertise.

Relations between gallery staff and management have been rocky since a two-month strike in 2001.

Franklin, who also served as deputy director, was considered a popular manager who provided doughnuts during the strike. He often replaced Théberge, his boss, at public events or conducting interviews with the media.

It was widely believed that the two men were not close colleagues.

Théberge's five-year term ended last December but was extended for a year by the federal government.

Théberge's e-mail said Franklin would be temporarily replaced by Mayo Graham, who has been the National Gallery's director of outreach and international relations for the past 10 years.

Graham is also a former director of the Ottawa Art Gallery.