Conte is guiding Chelsea to the Premier League title and faces former Blues boss Jose Mourinho at Old Trafford on Sunday in the toughest test of the run-in.
Ibrahimovic, who moved to United last season on a free transfer, has scored 28 goals in all competitions so far this season and earned a Player of the Year nomination on Thursday.
The Swede will miss out on a league title this season for only the second time since Ajax was pipped by PSV in Eredivisie in 2002-03 and scored 50 goals as PSG won four trophies last campaign, but Conte feels the 35-year-old is more dangerous than ever.
"I think he is in the top form of his career," Conte told reporters.
"I think now he is a great player, he is not just a finisher, it is good to have this type of player.
"He is very good to play for the team. For me he is one of the best in the world.”
Ibrahimovic will be looking to score for third Premier League game on the trot when Chelsea come to town on Sunday.