Rangers chairman Sir David Murray has accused Celtic counterpart John Reid of being too extreme in his condemnation of the "Famine Song".
Former Northern Ireland Secretary Reid has described as "racist" the song aimed at Celtic fans who claim Irish heritage.
The lyrics - which include the line "the famine's over, why don't you go home" - refer to the famine in Ireland in the 1840s which is estimated to have killed one million people and led to mass migration.
Rangers have taken steps to try to prevent the song being sung by their fans, including consulting police with a view to making it an arrestable offence.
But Murray claims Reid is making matters worse by not adopting a more measured tone when commenting on the issue.
"I find it strange that a man could become a member of parliament representing a whole broad church of people from Airdrie and Shotts, but then can also be the chairman of a football club and come out with a different slant," Murray told the BBC in an interview to commemorate the 20th anniversary of his acquisition of Rangers.
"I suppose he can say that because he knows he doesn't have to be re-elected to be Airdrie & Shotts again. I'm concerned by some of the comments. I give the utmost respect to Celtic football club - they've got a great tradition but I am recently a wee bit concerned by some of the inferences and innuendo that's come from John and I think he's got to be careful and realise he's not barracking in the House of Commons any longer.
"We are in a society in Scotland where every point and every word is picked up by everybody and he should be very careful with some of the chat."
Responding to Murray's criticism, Reid insisted he had no intention of remaining silent when he feels the need to speak out.
"I will continue to comment, when appropriate, without fear or favour," he said.
Murray will celebrate 20 years at Ibrox this weekend having bought the club for £6million in 1988.
He stood down as chairman in July 2002 but returned to the post in the summer of 2004.
Reflecting on a tenure which included a record-equalling nine league titles in a row, he said: "I've endeavoured to be as honest and as decent as possible. Hopefully, we can continue to win more trophies together. I think I'm the longest-serving chairman in the history of Rangers Football Club.
"I've done a fair innings with reasonable success. When it's time to walk, I'll walk. And I'll look back on it as an unbelievable experience and a privilege to be the chairman and major shareholder at Rangers."Reuse content