A PCB spokesman confirmed that the ACU had asked pacer Irfan and batsman Shahzaib to meet them on Tuesday in Lahore at the board headquarters.
"The ACU is not satisfied with the replies they got from both players regarding their interaction with some suspicious people in Dubai during the PSL. They have been called for questioning," he added.
"They will be questioned and if the ACU is not satisfied with their explanation than show cause notices will also be issued to them like in the case of Sharjeel Khan and Khalid Latif," he said.
The two Pakistani batsmen were sent back from Dubai during the PSL for their meetings with a suspected bookmaker.
The PCB also didn't clear left-arm pacer Mohammad Irfan for selection for the tour to the West Indies and his name was not included for the national training camp in Lahore.