The cabinet had been expected to approve the plan, a blueprint for eurozone accession which is periodically updated, at Tuesday's weekly meeting but the Peasants' Party (PSL) is unhappy about Tusk's proposal to reform farmers' pensions.
"I hope we will approve the convergence plan tomorrow. Everything indicates we shall," Tusk told a news conference.
Asked about the disagreement with PSL leader Waldemar Pawlak, Tusk said: "I don't think there is conflict in the coalition. Our temperaments are complementary and we understand each other very well, even when we have differing views."
"I think the concerns of PSL over the pension system changes are baseless," he added.
As part of a drive to reduce the government's budget deficit to 3% of gross domestic product by the end of 2012, Tusk has proposed bringing farmers, a privileged group in Poland, into the national pension system. This would require them to make bigger monthly contributions.
With parliamentary elections due in 2011 and opinion polls showing support for PSL hovering around the 5% threshold needed to enter parliament, Pawlak needs to show farmers, his party's base, that he is ready to fight for their interests.
Tusk added that if economic growth came in lower than forecast over the next few years Poland might only manage to bring its deficit down to the 3% of Gross Domestic Product level required under EU rules in 2013, not in 2012.
Last week, the government unveiled a fiscal consolidation plan that would cap budget spending and speed up the sale of state assets in order to check a sharp rise in public debt and to prepare the country for eurozone entry.
Analysts polled by Reuters see Poland, the EU's largest ex-communist country, joining the euro zone in 2014. Government officials have recently said 2015 is a realistic date.
Tusk also announced last week that, contrary to expectations, he would not run in a presidential election due this autumn because he wanted to focus on tackling Poland's economic problems as head of the government.
On Tuesday, Tusk confirmed that his centrist, pro-euro Civic Platform (PO) would probably field either Foreign Minister Radosław Sikorski or the speaker of the lower house of parliament, Bronisław Komorowski, as its presidential candidate.
"They each have different assets and I am not going to tell you who is my favourite," Tusk said, adding that he would not impose his own preference on the party.
In Poland, the prime minister and the government hold most power but the president can veto laws and also represents the country on the global stage. The PO wants to unseat President Lech Kaczyński because he has blocked a series of government reforms.
(EurActiv with Reuters.)