Saunders (23-0, 12 KOs) won the title last December against Andy Lee, in what was billed as the first world title fight between two travellers.
Saunders knocked Lee down twice in the thing round on his way to winning a majority decision.
The Hertfordshire boxer will be trading blows at the Copper Box for the second time, following a hard-fought clash with John Ryder for the British and Commonwealth titles in 2013.
With big-money bouts against domestic rival Chris Eubank Jr and Kazakh destroyer Gennady Golovkin on the line, the fight with Ukrainian contender Bursak is a must-win for the ex-Olympian.
— Frank Warren (@frankwarren_tv) March 14, 2016
Both Saunders and Bursak hold victories over current British champion Nick Blackwell. Bursak (32-4-1, 15 KOs), has lost three of his last six fights, including a defeat to former Saunders victim Jarrod Fletcher.
Bursak, a former European champion, will be fighting on British soil for the first time.
Both men promised to come looking for the knockout.
“I’m going to make sure I’m in perfect shape and give Bursak the toughest night he’s ever had,” said Saunders. “He’s never been stopped before so that’s something I’m looking at doing.”
Bursak replied: “I am telling Saunders to be prepared and train hard because he will be in for the fight of his life and I will be looking for the knockout.”
The 7,500-capacity Copper Box was the venue for handball, modern pentathlon fencing and goalball during the 2012 Olympics before its conversion into a multi-sport arena.