The Occupy Central organisers are hoping to sign up 5,000 supporters to donate HK$1,000 each to raise HK$5 million so that they can run deliberation meetings and electronic voting exercises.
Dr Chan Kin-man, one of the key organisers, said they were confident they would meet the target but if they failed they may have to scale back the campaign.
Chan said yesterday that the campaign would cost at least HK$6.8 million before summer next year. That included HK$2.15 million for two deliberation days, HK$2 million for two rounds of electronic voting, and HK$1.8 million for training and publicity.
The sum did not include any costs incurred if the proposed blockade of the city's business district went ahead. The movement plans to take action if the government fails to bring about genuine democracy for the 2017 chief executive election.
"The fact is we do not know how much the Occupy action would cost because it is not our prime concern at the moment," Chan said. "Our focus is reaching as many people as we can through deliberation meetings."
A key fundraising drive is to find 5,000 people to donate HK$1,000 each. Dinner events and a market involving 40 local shops are also planned.
Special guests at one of the dinners will be scriptwriter Chow Yuk-ming, who wrote TVB drama When Heaven Burns, writer Leung Man-tao and Benny Tai Yiu-ting, the other Occupy organiser. Entry will be HK$5,000.
Chan said all donations would be accepted provided they did not come with conditions.
"Anyone can donate to us, and their identity will be kept private," he said. "If we fail to reach the target we will have to set priorities for the funds. The deliberation days are the most important, but we might have to scale back other programmes."
The campaign has so far received HK$1.2 million, mostly from the July 1 rally, and more than half has already been spent. Of the 300 people who donated via their bank accounts, 40 per cent gave HK$1,000 and a handful gave HK$10,000 to HK$20,000.
This month and next month, up to 3,000 people will take part in a series of meetings - the second "deliberation day" - to forge a consensus on the "democratic principles" for the 2017 election.
A recent poll found 70 per cent of Hongkongers felt the campaign had only a slim chance of success, but Chan said it did not mean the plan lacked support.