The junior partner in Greece's ruling coalition will continue to support the government but there are limits to its support, a party spokeswoman said on Tuesday.
The spokeswoman of the Independent Greeks, Marina Chrysoveloni, also ruled out joining a coalition government with two opposition parties.
Prime Minister Alexis Tsipras faces a showdown with rebels in his own party furious at his capitulation to German demands for one of the most sweeping austerity packages ever demanded of a euro zone government.
"Independent Greeks have been constant in their support to the government, we have been supporting and we will keep on supporting the effort of the government," Chrysoveloni told state television. "However there are some limits too, that are shaped by the mandate of the Greek people, both in January's elections and in the referendum."