Ward is currently preparing to face unified light-heavyweight world champion Sergey Kovalev in November but it has been suggested that he may consider a move to 200lbs should he defeat the Russian in Las Vegas.
Bellew is currently being linked with a number of different opponents - including David Haye - but he has claimed that he would have no issue with facing Ward in the future.
The 33-year-old told Sky Sports News: "Andre Ward is, pound-for-pound, one of the best fighters in the world today. If he beats Sergey Kovalev, he probably goes down as the number one and what kind of fighter would not want to test himself against the pound-for-pound best fighter.
"If the opportunity arises and he wants to step up to my weight division, then I'm more than happy to put my belt on the line and give him a shot at being a three-weight world champion, but he wouldn't do so against me."