Employees of Swisscom have threatened to fight plans by the government to privatise Switzerland's leading telecoms provider.
A delegation handed in a petition to the finance ministry on Tuesday and warned of further job cuts.
More than 100 Swisscom workers staged a demonstration outside the ministry in Bern against government plans to privatise the telecoms company.
The unions, which organised the rally, said they would force a nationwide vote on the issue if parliament approved the privatisation.
They said the state's majority stake in the company had brought Swisscom a total of SFr12 billion ($9.2 billion) over the past seven years and ensured a basic telecoms service across the country.
Giorgio Pardini of the Communications Union said Swisscom employees had a right to be heard. He said the protest was possibly the beginning of a long battle against privatisation.
The protesters added that privatisation would lead to further job cuts and worsening labour conditions.
Swisscom has axed more than 6,800 jobs since the Swiss telecoms market was liberalised in 1998.
The government last month announced plans to sell its majority stake in the former state monopoly in a bid to give the company more strategic freedom of movement.
It also blocked any plans by the country's leading telecoms operator to make major acquisitions abroad.
Swisscom was close to concluding the takeover of Ireland's Eircom telecoms firm when the announcement was made.
The controversial decision sparked a public row within the seven-member cabinet and soured relations between the government and the Swisscom board of directors and management.
Both houses of parliament are due to discuss the row during the current winter session.
swissinfo with agencies
Swisscom, the country's leading telecoms operator, has a workforce of 15,288.
The company has axed more than 6,800 jobs since 1998 and is planning another 260 redundancies next year.
The government, which has a 66.1% stake in Swisscom, last month announced plans to privatise the former state monopoly.