The Sunday Mirror says the Latics believed they had sealed an £800,000 deal for the highly-rated young midfielder following his successful three-day trial at the DW Stadium just before the end of the season.
McArthur, 22, was looking forward to linking up with former Accies team-mate James McCarthy, who left the Scottish outfit in a £1.2million switch to Wigan 11 months ago.
But promoted Leeds have contacted Hamilton chairman Ronnie MacDonald and tabled a counter-bid of £1m with add-ons.
A source said: "Leeds are going for back-to-back promotions and, if they make it back to the top flight, then obviously they are a bigger club than Wigan."
McArthur said: "The prospect of a move really excites me. I am ready for it."