PRAGUE (Reuters) - Czech Prime Minister Bohuslav Sobotka rejected his coalition partner’s nominee for finance minister on Monday, extending a confrontation between the country’s two strongest political parties months before a general election.

Czech Prime Minister Bohuslav Sobotka speaks to journalists at Prague Castle in Prague, Czech Republic May 4, 2017. REUTERS/David W Cerny

Social Democrat head Sobotka said he would not accept Deputy Minister Alena Schillerova as a replacement for Andrej Babis, the billionaire businessman who founded the anti-establishment ANO, on the grounds that she was too close to her boss.

The prime minister has pushed hard to fire Babis for what he calls unanswered questions over his past tax dealings. Babis has denied wrongdoing and had refused to leave, but has come to accept his dismissal if his party chooses his successor.

Babis said he would submit a new name this week.

“Ministers don’t grow on trees, we have to find someone,” he told reporters. “We will try (to bring another name) by Wednesday, of course, the sooner the better. We want to end this.”

The row has become the most serious for the three-party coalition government, which came to power in 2014 and has been the most stable of any cabinet in the last 15 years, marked by a time of solid economic growth and record low unemployment.

With an election scheduled for October, Babis has called the scandal a political ploy by Sobotka, whose Social Democrats trail ANO in popularity by a wide margin.

Sobotka has raised questions about whether Babis may have broken the law in previous years by buying tax-exempt bonds from what was then his company, Agrofert, the country’s largest private employer active in agriculture, food, chemicals and media.

He called into question Schillerova’s impartiality in Babis’s tax matters in demanding a new nominee on Monday.

“I asked ANO to bring another proposal,” Sobotka told reporters after meeting Babis. “I do not have confidence that Ms. Schillerova would be able to guarantee a truly intensive, thorough performance of financial administration and the ministry on (Babis’s tax operations).”

The coalition, which also includes the Christian Democrats, had rejected snap elections, but that could change if ANO’s nomination for the finance ministry were rejected again.

Under the Czech constitution, 101 votes in the 200-seat lower house of parliament are required to topple a government and a three-fifths majority is necessary to dissolve the chamber and force early elections.

President Milos Zeman has taken Babis’s side in the dispute and has been delaying action. When Sobotka threatened his own resignation, which usually means the fall of the entire government, Zeman hinted he could keep it in place and only replace the prime minister.