Greece launched a tender to sell off ailing state carrier Olympic Airlines on Tuesday, but unions and pilots vowed to step up protests to block any possible sale, Reuters reports.

Greece announced earlier this month it would break the loss-making airline into three units and privative them, ending years of failed efforts to find a single buyer and wrangling with Brussels over illegal state aid.

"The buyer...will be selected through a multi-stage process," an official tender statement said. "It is envisioned that a number of qualifying interested parties will be allowed to participate in the next stages of the process."

Olympic has long been a burden on Greek taxpayers as a bloated workforce and generous bonuses made the airline loss-making even on its most profitable routes. The carrier had estimated debts of about 2 billion euros ($2.86 billion) at the end of 2007.

Successive governments tried and failed to offload the airline but faced constant and stiff opposition from its powerful unions, a prospect that is set to continue.

Hundreds of workers from Olympic and associated unions blockaded Greece's Transport Ministry on Tuesday, setting off firecrackers, lobbing rocks and bottles into the building, and chanting slogans calling on the government to scrap the sale.

"We demand that the government withdraw its plans for Olympic, and we will continue to protest until it is dropped," Manolis Patestos, head of the Olympic Airlines' employees unions (OSPA), told Reuters.

Workers fear they will be without jobs, despite repeated government assurances that all of Olympics' more than 4,500 core employees will be redeployed to other public service positions at equal pay or get lucrative early retirement packages.

Its 3,500 seasonal employees will be given preferential treatment for other government jobs and given access to special training programs, officials have said.

"We do not want the company to close or to be sold. I will be forced to go into early retirement, while I have another seven years to go," said Nikos Mikropoulos, 51, an aircraft mechanic for Olympic.

Last week, Greece's privatizations committee gave the green light for the launch of a tender for three new holding companies that will replace Olympic's airline services, ground handling, and technical maintenance departments.

The holding company covering airline services will be called Pantheon and will have the right to use the existing Olympic name and logo. It will have certain valuable airport slots and the possibility of acquiring other Olympic assets such as aircraft and IT systems, the statement said.
After the initial stage of expressions of interest, qualified parties will be allowed to proceed to due diligence for them to prepare their bid, the government statement said.

Lazard, NBG International, Alpha Bank and Emporiki Bank are advising the government on the sale.