PRAGUE (Reuters) - A junior partner in Slovakia's ruling coalition, the Slovak National Party (SNS), surprised its partners on Monday by pulling out of an agreement underpinning the government and calling for a new deal.


Prime Minister Robert Fico described the SNS move as "absurd", though the end of the deal does not automatically spell the end of the three-party government, in power since March 2016, or a new election.


SNS chief Anton Danko, who also serves as the speaker of parliament, said in a letter to his coalition partners that his party sought new coalition rules.


"The reason is the absolute necessity to reset rules in the coalition, the new shape of conditions and relations and absolutely new priorities," Danko said in the letter in which he also offered to hold talks.


The government needs the votes of all three coalition parties -- the nationalist-conservative SNS, Fico's center-left Smer and the ethnic Hungarian party Most-Hid -- to maintain a majority in the 150-seat parliament.


Fico called a meeting of the three party leaders for Tuesday morning where he wants Danko to explain his steps.

"(This) is not bringing calm and stability," Fico's spokeswoman said in a statement.

The chief of Most-Hid, Bela Bugar, said on TA3 television he was surprised by the SNS decision.

A formal resignation of the cabinet could follow a vote of no confidence that would lead to the formation of a new government or a new election. A regular election is due in 2020.

Danko said in his letter that the government needed a new program to reflect Slovakia's strong economic growth.

"The good socio-economic situation of 2017 shows that we have to focus on new challenges and priorities that need to be reflected in the coalition agreement and a new program manifesto," Danko said. "When a country's economy is doing well, the people should feel it."

Slovakia, a member of the European Union since 2004 and of the euro zone since 2009, saw unemployment fall to an all-time low of 6.9 percent in June. The economy grew 3.1 percent year-on-year in the first quarter.

Miroslav Ciz, a deputy for Fico's Smer, told news website he believed the situation would calm down.

"I believe common sense will prevail," he said.

Several opposition leaders said Danko was trying to divert public attention away from criticism of the distribution of EU subsidies for research programs in the education department led by his party.

(Reporting by Robert Muller and Jan Lopatka; editing by Gareth Jones)