Romney played 'Wavin' Flag' during his acceptance speech after winning the Florida Republican primary on Tuesday (January 31).
K'naan has now claimed that he would never have given the Romney campaign permission to play the song at their events and ordered them to refrain from using 'Wavin' Flag'.
The politically-aware rapper said in a statement that he would, however, allow US President Barack Obama use of 'Wavin' Flag' for similar campaign events.
A Romney campaign spokesperson told The AP they had used the song under its regular blanket license, but would no longer play it at their political rallies.
'Wavin' Flag' became an international hit when it was released in March 2009 and was even used as an anthem for the 2010 World Cup.
K'Naan, who was born in Somalia but grew up in Canada, has been a leading advocate to end drought in East Africa. Last year, he joined country music star Kenny Chesney in a performance to honour the William J Clinton Foundation.
Watch K'Naan's 'Wavin' Flag' music video below: