The British Olympic Association has called on Scotland to rethink its plans not to take part in a Great Britain football team in the 2012 Olympics.
England and Northern Ireland are in favour, while the Welsh Football Assocation has yet to decide.
BOA chief Simon Clegg told BBC Sport: "The door is still to open to Scotland and Wales to collaborate.
"The Scottish Football's approach is disappointing given the assurances they've been given by Fifa."
Sports minister Richard Caborn has also called for the Scottish FA to reconsider.
He said: "Football is our national sport and it is really good news that
there will be Team GB sides in 2012.
"I hope that the Scottish Football Association may yet reconsider their
decision not to participate in the British teams.
"We have received clear assurances from Fifa that taking part would not compromise the separate status of the four home nations in international football.
"This should be a Games for the whole of the country, with everyone involved, sharing in the excitement and the real benefits the world's greatest event will bring."
The BOA is to release an opinion poll which it says provides strong backing for the idea of a Great Britain football team made up of players from the four home associations.
The survey of 1,000 people showed 75% either strongly supported or supported the idea of a GB football team in the London Olympics, with 69% backing in Scotland.
"The BOA believes the British public are behind the idea of team GB football in 2012," added Clegg.
The Scottish FA had been given written assurances by Fifa president Sepp Blatter that taking part in the 2012 Games would not affect their separate identity in world football.
But the Scots fear that Blatter may not be in power in 2012 and his successor may have other views.
An SFA spokesman said: "We are just being entirely consistent with the position we have held for years."
Wales are set to follow Scotland's example by refusing to participate in a GB football team in 2012.
The FA of Wales believes playing in such a team would jeopardise its status as a separate football nation.
"It would give ammunition to the people who want the four home nations to play as one Great Britain team," said FA of Wales secretary general David Collins.
Wales will make a final decision at next month's council meeting.