Seks praised Tadic for expressing regret for innocent victims and for apologising for the crimes committed by Serb forces during the 1991-1995 war in Croatia.
"This is an important step forward which will make a substantial impact on relations between Croatia and Serbia and on the strengthening of stability in the entire region," Seks told reporters in the Parliament building.
Antunovic said that the apology was welcome.
"Since such an apology was not made before, it is good that it has been done now," she said, adding that apologising required courage.