Illyas was banned from Gaddafi stadium in Lahore in April after a row about the selection of the squad for a one-day series against Sri Lanka in Abu Dhabi, Nagmi said.
"The ban can be lifted if Illyas approaches us and apologises for the incident," he added.
Another PCB official, who did not want to be named, said Illyas had threatened to "start a war" with the selectors after the omission from the squad of his son-in-law, Pakistan opener Imran Farhat.
Farhat was also fined and reprimanded in April by the board for approaching the selectors and demanding an explanation for being left out of the squad.
Illyas, who played 10 Tests for his country, said he had been unaware of the ban until he heard about it from a third party.
"I was just upset over the way they selected the team for Abu Dhabi and I vented my anger but I have never harmed anyone in my life," he added.