"It is October 12 at 9am," an official from the technical department of the Jiuquan Satellite Launch Centre, who refused to be named or comment further, said on Monday.
But the China National Space Administration said it could not confirm the date, which has been shrouded in secrecy.
"It is up to the people at the scene. Only they can decide the date and the time," said a spokeswoman at the international affairs department.
However, a travel agent taking domestic tourists to witness the launch said he had been advised to be at the site early on Wednesday morning.
China's state-run press has reported that Zhai Zhigang and Nie Haisheng would probably pilot the five-day mission, which will return to earth in the grasslands of Inner Mongolia.
The flight comes almost exactly two years after the successful 15 October 2003 launch of astronaut Yang Liwei into space, making China only the third nation after the United States and the former Soviet Union to accomplish such a feat.
During his 21-hour trip to space in 2003, Yang never left the re-entry capsule, but this time will be different.The two astronauts are expected to enter into the orbital module in the front to conduct a large number of tests, many of them presumably designed to check their physical reactions to conditions in space.