After the meeting, Seks, who was on a two-day return visit to Kiev, said that Croatia had been given guarantees that gas supplies which go from Russia via Ukraine to Croatia would be regular and their price acceptable.
"We have been assured that gas supplies for Croatia would remain at the same level and that Croatian interests would not be jeopardised," Seks said at the end of his visit to Ukraine.
On Monday, Seks held talks with his Ukrainian counterpart Volodimir Litvin and the acting Prime Minister Yuri Yekhanurov and Foreign Minister Boris Tarasyuk.
At the start of this year, an argument erupted between Russia and Ukraine over the price of gas supplies which the Russian company Gazprom delivers to Ukraine. The crisis resulted in occasional obstructions of gas supply to Europe. The situation has defused, but the Ukrainian government led by Yekhanurov did not survive a no-confidence vote in the national parliament.
Yekhanurov remains the acting Prime Minister until regular parliamentary elections set for late March. President Yushchenko has accused the parliament of having destabilised the country.
"Croatia has expressed its support for the stability of democracy in Ukraine. We have told our hosts that Croatia is interested in seeing Ukraine having a stable government and parliament," Seks told Croatian reporters after he met Yushchenko.
The Croatian delegation on Tuesday also visited the "Antonov" aircraft manufacturing factory.