Speaking to the press on Friday, Billy Begley, who still lives in north Belfast, said to his knowledge, the event planned for next Saturday near his home is going ahead.
He said the family would mark the anniversary "in our own way" and that they would have preferred a private memorial.
A leaflet which has been circulated, featuring an image of gunmen firing into the air, says that "friends, family and comrades" will host the event.
Nine civilians, including two children, were killed in the blast at the shop in October 1993. Begley was also killed when the bomb exploded prematurely.
The IRA said the intended target was a flat above the shop where loyalist paramilitaries were expected to gather, but the meeting did not go ahead.
Mr Begley told the Belfast Telegraph Begley's mother Sadie didn't want a plaque erected.
He added that the family had nothing to do with organising the event or putting together the leaflet publicising it.
"It's only a commemorative plaque - we're not glorifying the bomb," he added.
"There is no way we're glorifying it. We feel sorry for the people who were killed. There's no bands or anything."
Mr Begley said he would have prevented his son from taking part in the bombing if he had known of his plans.
"If I'd known that day, I'd have chained him to the bed," he told the paper.
"He was a good lad, he just got involved and that was it."