The centre-back, 26, has agreed personal terms with the club and the move is expected to go through on Friday.
Iriekpen was stripped of the Iron captaincy and placed on the transfer list last month.
It followed the 4-4 home draw with Northampton Town, a match where Iriekpen's performance was criticised by supporters and the Iron manager Nigel Adkins.
Billy Reid, the Hamilton manager, was delighted to secure the signing.
"He was the captain of Scunthorpe, and they wanted him to sign another contract. But I think he refused; he wanted to play at a higher level," he said.
"They decided it would be better for him to go, and we got word of that. He's a player with decent pedigree, and we're delighted to get his services.
"He's played 19 times for Scunthorpe this season and scored four goals from set-pieces, so he's a threat at the other end of the park."
Iriekpen could be in the Hamilton squad to play Kilmarnock on Sunday along with Kenny Deuchar, another new signing.