Police are bracing for the logistical and security challenge of dealing with nearly 60,000 protesters in the heart of Central, when opponents and supporters of the government converge on the Legislative Council building on Wednesday.
The force says the area outside the legislative building, Edinburgh Place, Statue Square and the open area at the base of HSBC tower can only accommodate 10,000.
They are hoping to funnel the bulk of the crowd into other areas - understood to include the Tamar site.
Deputy Police Commissioner Dick Lee Ming-kwai yesterday said police had no plans to cordon off any roads in the area as this could disrupt activities in the heart of the city's financial centre which he said could not afford any major obstruction.
'Fifty-thousand people, as you can imagine, means a fully seated Hong Kong Stadium, including the turf area. If you put all these people in Central, it will certainly lead to congestion,' Mr Lee said.
Police say they are working on a solution with one of the rally's organisers, the Civil Human Rights Front, which on Friday raised the initial projected number of participants from 2,000 to 50,000.
The group, which organised the 500,000-strong protest on July 1, said it readjusted the number after taking into account growing public discontent.
It said it would go ahead with the rally despite the government's decision yesterday to further amend the national security bill.
The police have also received notification from three other groups which plan to stage rallies to support the legislation relating to Article 23 of the Basic Law. The groups are the Hong Kong Island Federation, Kowloon Federation of Association and North District Residents Association. The supporting groups will hold rallies involving about 8,300 people.
The force has also approved another 300-strong anti-national security bill rally organised by Falun Gong.
Mr Lee said if the crowd became too big, police would ask people not to go to Central or would lead them to other places.
Mr Lee said the public order situation in Hong Kong remained stable and they had not stepped up the protection for Chief Executive Tung Chee-hwa, who has been the main target of public outrage.
But a spokesman for the Civil Human Rights Front, Richard Tsoi Yiu-cheong, said it would be irrelevant for either police or protest organisers to set a quota on numbers at Wednesday's rally.
'It's not something for us to say. Many people will join us if Mr Tung insists to go ahead [with putting the legislation to Legco] next week.
'We call on the public to go to Legco at 1pm that day or 7.30pm to join the rally to continue to oppose the legislation on Article 23 and fight for a referendum on the chief executive,' Mr Tsoi said.
The group expects the biggest crowd to gather in the evening.