A fresh controversy over sectarian singing erupted last night when Gregory Campbell, the Northern Ireland Sports Minister, said that he was unlikely to accept an invitation to Celtic Park after IRA chanting by the club's supporters.

The Democratic Unionist Party MP has written to John Reid, the Celtic chairman and former Northern Ireland Secretary, to complain about IRA songs sung by Celtic fans at a game against Motherwell last week.

In his letter, written in his capacity as MP, not Sports Minister, he demanded that the club take more action. He felt that Rangers had taken steps in the wake of a recent controversy about their fans taunting Celtic supporters at an Old Firm game.

The MP called on Celtic to follow suit - otherwise any visit to the club could prove “counter-productive”, he claimed.He added in his letter that he had praised both sides for their work on tackling sectarianism.

The latest row comes after Irish diplomats raised concerns with the Scottish government over Rangers fans chanting the controversial “famine song”, which refers to the Irish potato famine.

Mr Campbell had been invited to Celtic Park after he and his wife were subjected to sectarian abuse by fans on a ferry crossing. But in the wake of the latest incident, the East Londonderry MP said that he believes a visit to Parkhead would send out the wrong message.

The invitation from Celtic was for the MP to see the good work done by the club in tackling sectarianism. Mr Campbell said: “If I go over to see some of the good work that's being done, and I experience some of the things reported to me, that could be counter-productive.”

The MP emphasised that he had not been planning to visit Celtic Park soon, but he said that the IRA chanting meant that any visit was now less likely. “It's probably made things a bit worse,” he said. He insisted that he was not “setting preconditions” to visit Celtic Park, but said more action should be taken against the small number of fans involved in chanting.

Despite the conflict in Northern Ireland being officially over, IRA chants were still a sensitive area, Mr Campbell said: “Memories are still fresh about the pain it brought on all communities.”

A Celtic spokesman said: “We are pleased that Mr Campbell recognises the great work that Celtic has carried out in tackling sectarianism.” He said the club had received details of the chanting incidents from Mr Campbell. “It will certainly be considered with representations we have received in relation to racist and sectarian chanting from supporters of other clubs,” the spokesman said.

This week, Alex Salmond, the First Minister, agreed to introduce a national anti-sectarianism strategy, after criticism from Jack McConnell, the former First Minister, that he had been weak on the issue. Asked by Bill Butler, Labour MSP for Glasgow Anniesland, at First Minister's Questions, if he would back a strategy, he said: “Yes, I can give that commitment, because it will give us an opportunity to focus attention on - and to have more widely understood - the range of anti-sectarian activities that are promoted by the government.”

He invited the Parliament to unite behind an effort to stamp out “the evil of sectarianism”, and described it as “one of the great social challenges that Scotland faces”.

Police investigating an assault on Neil Lennon, the former Celtic captain, have released video footage and still images of two men they want to trace. Mr Lennon, 37, who is now a coach at the club, was treated in hospital for minor injuries after an incident in Glasgow's West End, hours after an Old Firm match.

The former midfielder from Northern Ireland was assaulted in the city's Ashton Lane, well known for its fashionable bars and restaurants, in the early hours of September 1.

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