An announcement of the winner to redesign the square was due on Friday, 18 January, but is being delayed after the jury was unable to choose from the shortlist of six practices. They include Gustafson Porter, Burns + Nice and Gillespies.
"Panel members have been considering designs from the six short-listed companies taking part in the international competition," said the city council on Friday. "But the jury has so far been unable to reach a decision and they are now not all available to reconvene until next week.
"The £15m project caught the imagination of the international design community, with Glasgow City Council receiving 35 submissions to redevelop the square from as far afield as Australia, the USA and Sweden."
Judge panel member and council leader Gordon Matheson said: "It is disappointing but important we get this right. We will make a decision next week."
The redevelopment work is due to be carried out in two stages, the first being completed before the Glasgow 2014 Commonwealth Games. Funds will come from an investment programme from the Buchanan Quarter TIF Business Case.