The Bjelolasica event drew some 2,000 HNS members.
Speaking of the strength of this opposition party, which he said had 40,000 members, Cacic said the HNS was ready for victory at the parliamentary polls, whether they were held next spring or in 15 months' time.
Cacic accused the current government of incompetence which he said pushed the Croatian people into a deep mire.
Vesna Pusic, head of the HNS caucus in the parliament, greeted representatives of the Croatian Pensioners' Party (HSU) and its leader Silvano Hrelja, who were also at Bjelolasica.
She said that agreement between the HNS and HSU in the parliament was "the embryo of the future victorious coalition at the forthcoming parliamentary elections."
Responding to reporters' questions, Cacic said the number of signatures collected by trade union federations on labour legislation was a blow to the legitimacy of the incumbent government.
"830,000 signatures are actually a demand for the departure of this government," Cacic said.
The HNS will propose that EUR 510 million be ensured in a revision of the budget for pre-financing and co-financing projects in units of local-self-government.
The HNS will move in the parliament the allocation of funds in the amount of 15 percent per project for drawing money from European Union funds.