Though the Shanghai Stock Exchange said 89 brokerages are qualified to run the business under the Shanghai-Hong Kong Stock Connect scheme, the specific date is still unknown.

"We don't have a timetable," said Li with the Hong Kong exchange.

"Whether it's announced today, tomorrow, the day after, two days after, or any other day, is not important. People shouldn't read too much into the timing of it. The main issue is that we are prepared for the starting gun," he said, adding that any announcement of the start date won't be made "unilaterally."

China's A shares, have remained mostly bearish since 2008, and have been showing signs of resurgence this year, largely due to the optimism over the Stock Connect program and expectations that liquidity from offshore investors would prop up undervalued shares.

The benchmark Shanghai Composite Index has surged by almost 15 percent since Li Keqiang announced in early April that the program would start in six months. The exchange link will allow mutual market access to a broad range of shares in both the bourses, the equivalent of $1.7 billion in daily net purchases of Hong Kong shares and $2.1 billion for Shanghai.

Hedge funds wait for green signal to ride 'through train'	Cross-border stock program offers change at the margin