Tomcic added that agreement to that effect had been reached in 18 counties and that it was expected in the remaining three.
The HSS leader and other party officials were on a visit to the eastern town of Djakovo where they attended a programme marking the party's 100th anniversary, organised by the local HSS branch.
At a news conference Tomcic also spoke about threatening letters that he received.
"Over the past five or six years I have received about a dozen such letters, but the last one is indeed serious, so I decided to inform the police. There is no doubt that the threats come from the political underground and that they are part of a campaign because several other MPs have received such letters as well," Tomcic said without going into any details.
Commenting on the current political situation in the country, Tomcic said that lately it was marked by scandals.