"Until all the facts have been established, it would not be fair of me to comment on the case," Mesic briefly told reporters at the Hotel Opera in Zagreb where he was attending a regional conference entitled "Small countries and challenges of managing economic globalisation".
Mesic noted that he had the same information on the case as journalists did.
On Wednesday, the former head of the Parliament Commission on Conflict of Interest asked Zuzul to resign following media reporters that he was in conflict of interest.
According to allegations by parliamentary opposition parties and media reports, there were five transactions worth a total of 143,000 kuna between Karin Univerzal and MTS, the company owned by Zuzul's wife Tatjana.
Zuzul recently rejected all the allegations, including the one that he was in conflict of interest when the government decided to write off the debt of Imostroj, an ailing company that had been bought by Karin Univerzal, which had previously done business with Zuzul's wife.