Speaking at a municipal election rally in Grude on Thursday, Dragan Covic said the division attempt was based on a scenario whose authors were both in Bosnia and Herzegovina and outside the country.
Covic's political opponents in the party, led by Bozo Ljubic, demand that he step down because they claim his election to the presidential post was irregular.
In Sarajevo two days ago, Covic and Ljubic held separate meetings with Wilfried Martens, president of the European People's Party, in which HDZ BH has observer status.
Martens asked them not to speak in public about what their talks, and while some Bosnian media claimed that Covic would have to step down by the end of the year, other media said Martens had not asked him to do so.
At the Grude rally, Covic called for unity within the party. He said he attended many HDZ BH panel discussions around the country about constitutional changes in recent weeks, and that the establishment of a third, Croat entity was proposed at each one, except in Zepce.
Commenting on a recent proposal by the Bosnian Bishops' Conference to replace the two existing entities with four regions, Covic said the HDZ BH would not take a position on this proposal.