Mr Hay had stern words at Stormont for those who did not turn up for the afternoon session, a practice which he said could not go on.
There were a number of empty seats in the house for questions to Employment and Learning Minister Stephen Farry.
"There was quite a few members who were not in their places for question time this afternoon and I don't know any other elected institution where that would be tolerated," he said.
"I would expect these members who have not been in their place this afternoon, that the first opportunity they have, they will come to this house and they will give a reason."
"Members who for whatever reason feel that they can't do that, I can assure members we will deal it, and deal with it properly and procedurally," he added.
"It cannot go on that members just don't turn up and don't give a reason and certainly if it continues I will deal with it, but from here on in I would expect members to give a reason and to apologise to this house."
Just a few months ago MLAs were issued with a written warning after they did not turn up when they were scheduled to ask questions. Deputy First Minister Martin McGuinness said the situation was a disgrace.