Oppostion party leaders have called for Derek Mackay to resign or face disciplinary action from the SNP after he quit as Finance Secretary.

Labour leader Richard Leonard said Mr Mackay's actions were "predatory" and said deserves further action."

Mr Mackay gave his resignation letter to Nicola Sturgeon after it was revealed he had been sending inappropriate mesages to a 16 year-old boy.

Ms Sturgeon is due to make a statement at noon to the Scottish Parliament but Labour, Tory and Lib Dem leaders have said the ministerial resignation is not enough and his position as a Member of the Scottish Parliament is untenable.

READ MORE: Derek Mackay quits as finance secretary over 'inappropriate' message scandal

Richard Leonard, leader of the Scottish Labour Party said: “Derek Mackay has acted beyond ‘foolishly’, his actions are predatory and must be thoroughly investigated. He has abused his position of power with a vulnerable adolescent.

“The thoughts of everyone at Scottish Labour are with the schoolboy involved and his family.

“The nature and the gravity of these allegations demands decisive action. “

Jackson Carlaw, Scottish Conservative leader, said: "The First Minister is going to be making a statement before First Minister's Questions this morning.

"I don't think she believes that simply accepting his resignation from Government is an end to the matter.

"I think there will be huge question to be asked, parents who will be concerned, and I think many colleagues in parliament who will wonder if Mr Mackay can continue to enjoy the confidence of his constituents or Parliament."

Willie Rennie, Scottish Liberal Democrat leader said it was a "troubling series of events, and not just for the family" and that Mr Mackay had to go as an MSP.

He said: "It's about the standards we expect as an MSP. Derek Mackay has not behavied in the way we would expect. It's time for him to resign."