SDLP leader Colum Eastwood said he accepts a tweet he posted in response to an image of Seamus Heaney being used to commemorate Northern Ireland's centenary "wasn't nuanced enough".
Mr Eastwood has spoken of his regret at the Twitter post, but said he still believes it was wrong of the Northern Ireland Office to use the Co Derry poet's image.
A colour painting of the Nobel laureate, who was born into a rural Catholic family in Bellaghy, appears in the "Our Story in the Making: NI Beyond 100" initiative.
It is also not known if his family, who have not commented, were consulted about plans to use his image.
Henaey, who died in 2013, once famously wrote: "Be advised, my passport's green / No glass of ours was ever raised / To toast the Queen."
Mr Eastwood last month described the use of Heaney's in the branding as "deeply offensive" and tweeted an image of the poet alongside his quotes about a toast to Queen Elizabeth.
However, the Foyle MP spoke of his regret about the tweet.
"I probably should have put out a statement before going on Twitter," he told Belfast Live.
"I think sometimes on Twitter you try to get a point across in a stark way because you've only got so many characters.
"I regret that people thought, genuinely do, that people felt that I was I suppose minimising it.
"It wasn't nuanced enough, I didn't put it into context and I think that's a fair criticism, but I still stand by the fact that I thought it was wrong to use somebody's image who clearly probably wouldn't have supported the use of their image if they had of been alive, so I think that was a mistake."
Mr Eastwood said he still believes it "would have been a good idea for the NIO to talk to his (Heaney) family before they would use his image".
