The governing World Professional Billiards and Snooker Association (WPBSA) said in a statement on Tuesday that the suspension from attending or competing was with immediate effect.
"This decision is part of an ongoing investigation into allegations of manipulating the outcome of matches for betting purposes in breach of the WPBSA Conduct Regulations," it said.
It added that the investigation was expected to be completed shortly, "at which point any potential charges will be considered".
Reuters has sought comment from the players, who have the right to appeal.
Zhao, who won the 2021 UK Championship and last year's German Masters, is ranked ninth in the world and had been due to compete in The Masters invitation event which starts at London's Alexandra Palace on Sunday.
Zhang is ranked 82nd in the world.
China's Chen Zifan, Lu Ning, Li Hang, Zhao Jianbo, Bai Langning, Chang Bingyu and former Masters champion Yan Bingtao were suspended in December. Liang Wenbo was suspended in October.
