"I would not be happy with a postponement," Sanader told reporters after a meeting with the leaders of parliamentary parties and the first session of the National Committee for the Monitoring of EU Entry Talks in Zagreb on Monday.
Those proposing a postponement must explain the reasons and there must be mutual sincerity, he added.
Sanader is certain that Croatia has managed to convince the last sceptics that full cooperation with the UN war crimes tribunal does not mean General Ante Gotovina being in The Hague, but rather that Croatia is doing its utmost to see that he gets there.
The PM said that Croatia would on Tuesday try to convince the remaining sceptics in Brussels, who he said might not possess all the information.
According to Sanader, the group that is advocating the start of the talks on 17 March is quieter but in a majority, while the group in favour of delaying the talks is smaller but more vociferous.
Sanader went on to say that he would like to see the EU being unanimous in accepting Croatia's assertion that it is sincere, credible and that there are no double games.
Sanader said that his proposal that the European Commission send a group of observers to monitor Croatia's cooperation with the tribunal was well accepted even by some countries that had not initially been leaned towards launching the talks.
"We shall wait for tomorrow's meeting between the tribunal's chief prosecutor Carla del Ponte and the Luxembourg Foreign Minister, as it is important who will verify Croatia's efforts and cooperation and whether it will be the EU," he said.
The PM does not believe that posters with the image of the fugitive general Gotovina appearing occasionally in Croatian towns can thwart the start of the talks and claims that it has nothing to do with his cabinet's credibility.
Sanader bases his optimism about the start of the entry talks on 17 March on the fact that Croatia has done its utmost to solve the last remaining issue in its cooperation with the International Criminal Tribunal for the former Yugoslavia (ICTY).
The head of the National Committee and leader of the strongest opposition Social Democratic Party, Ivica Racan, however, is less optimistic and hopes that if the talks are postponed, the delay will not be too long.
I would like to see the government persuade the sceptics in Europe, and I do not want to speculate about whether it will succeed in doing so, Racan said.
He announced the next session of the National Committee in a week's time, when the final decision on the start of the talks should be known.