Magpies boss Alan Pardew confirmed the move of the Frenchman, who struggled to break into the first team at Old Trafford.
“He will be here on Monday and we are looking to seal the deal,” he told Sky Sports News.
“He is a player who hasn’t had too many opportunities. He is quick, he will add pace to our team. I am looking forward to seeing him.
“We are working on one or two things.”
Obertan made 14 appearances for United since joining from Bordeaux in 2009 for a fee thought to be around £3m.