The disgruntled workers said they would remain in Zagreb until their requests are addressed.
The trade unions that organised the protest insist on the resumption of the production in the "Zeljezara Split" without having the company going into official receivership.
A majority of the 400 workers on the steel mill's payroll have not been working for a year and a half, as parts of the mill have been closed.
All this time they have been receiving a minimum monthly pay of HRK 2,000.
The dissatisfied employees also insist on the cancellation of the agreement with the company's current owner, Poland's Zlomrex concern.
The Polish company today stated that it was considering the solutions proposed by the Croatian Privatisation Fund (HFP) and that it would need a few more days to voice its final position on the proposals.
Although the offer made by the Fund reduces the price for the steel mill from EUR 10 million to nil, Zlomrex is considering it, the Polish company said in a statement.
As this offer has significant financial and legal implications for Zlomrex, in the event of its acceptance, we need a few more days to give our final view on your offer, the statement reads.
The Fund's president, Vedran Duvnjak, said that Zlomrex's response had just arrived and that it would be discussed later in the day.
The two solutions for the ailing Zeljezara Split were presented at a recent meeting of the company's workers and unionists with the privatisation Fund and the Economy Ministry.
One of them is to peacefully terminate the agreement with Poland's Zlomrex, which should then sell its claims and a stake in the steel mill to the Privatisation Fund at the price of one kuna. In return, the Fund would no longer insist on payment of corporate guarantees in the amount of HRK 87 million. This would enable the Fund to become the owner of the Split-based company.
The other solution is to seek the enforcement of corporate guarantees in court. This will probably lead to the plant's bankruptcy due to its overindebtedness.
Later on Thursday, the protesting workers said they would accept talks only with Prime Minister Jadranka Kosor, adding that they would no longer meet with Fund's president Duvnjak who they said did not believe any longer.
They also expressed their vociferous opposition to possible bankruptcy proceedings for the steel mill.