A coalition of more than 20 labour unions and a students group say they will ballot thousands of members on June 14 on whether to hold a general strike against the national security law which Beijing is preparing for Hong Kong.
As of Saturday, the trade union alliance includes 23 members, covering sectors like transport, IT, catering, accounting and medical workers.
It said a referendum is the most accurate way to determine members' views on the matter.
The group admitted that a strike called earlier fizzled out because there has been no proper organisation and a mutual trust on the matter.
The alliance said only if at least 60 percent of the more than 60,000 expected voters approve the idea in the referendum, they will consider further action.
They said, if approved, they plan to launch the strike in phases, with about three days of industrial actions in ways like taking sick, annual or no-pay leaves as the first phase.
If the government doesn't have any response, it said they may go to the second phase that involves calling on members to be absent from their duties.
The group's spokeswoman, Cat Hou, said on Saturday the aim of the strike is to stop the planned national security law.
She called the planned vote as "the first-ever referendum on general strike" in Hong Kong,
The aim is to amplify the voice of the vast labour force to show the international community their view on the national security law, she said.
She claimed that the possible general strike could involve tens of thousands of people in the next few months.
The Confederation of Trade Unions' chairwoman, Carol Ng, has thrown her weight behind the proposal.
Meanwhile, an alliance with secondary schools have also planned to hold a similar referendum on the same day, asking pupils whether there should be a school strike as well.
It said students can vote online or cast a ballot at booths they plan to set up on June 14.
They said they hope to get feedback from over 10,000 secondary students and if 60 percent agree, they will organise a school boycott.