Winger Smith (pictured) has had a positive impact for the Lions since arriving on loan from league rivals Wrexham in early November, while full-back Hurst has also featured prominently following his arrival from another National League outfit, Torquay United, in the same month.
Both Smith and Hurst will now remain with the club for the remainder of the season.
Manager Mark Bower said: “We’re delighted to be able to make Adam and James permanent members of our squad.
“Both have demonstrated their qualities while with us on loan and I’m convinced they will continue to do that as we seek to preserve our National League status.”