Bank of Nova Scotia CEO Richard Waugh said he was too optimistic about the swift completion of a deal to buy a stake in a Chinese lender.

Scotiabank has been awaiting regulatory approval from China on a deal announced in 2011 to buy a 20 percent stake in Bank of Guangzhou Co for C$719 million ($698.9 million).

"We were a little too optimistic on that first announcement," Waugh, 65, said on Wednesday at the Bloomberg Link conference in Toronto. "I'm not going to make the same mistake twice and be optimistic again. We are still seriously trying to move this along."