By Chris Hogg
BBC News, Hong Kong
Pro-democracy lawmakers from Hong Kong are due to cross the border into mainland China for a rare face-to-face meeting with senior Beijing officials.
Democracy activists are demanding a timetable for change
It comes two days ahead of planned protests in the territory against the Hong Kong government's proposals for limited constitutional changes.
Hong Kong's pro-democracy camp is unhappy with the plan.
It is demanding a timetable for the introduction of universal suffrage instead.
The meeting in the southern Chinese city of Shenzhen is with the deputy secretary general of the Chinese legislature's standing committee.
The Hong Kong democrats have accepted the invitation in the hope that the official will pass on their views to his bosses in Beijing.
They are unhappy with the government's proposals to tinker with the system for choosing the next leader of Hong Kong in two years' time, and the next legislative council after that.
Beijing has told the people of Hong Kong they will not be allowed to vote to choose who rules them in 2007.
But the democrats argue they should be told when in the future they will be given the chance to elect the chief executive and their lawmakers.
Without such a timetable they will not support the government's plans, they say.
The Chinese will hope that by holding the meeting, they will look like they are listening to concerns of the pro-democracy camp.
That could undermine the momentum for protest.
But it is a risky strategy.
The Shenzhen meeting and a direct appeal on television this week by Hong Kong's leader are drawing more attention to the democrats' concerns, and could yet bring more people onto the streets this weekend to support them.