Samaras' own center-right New Democracy party was expected to vote in favor of the package.
Although the third coalition member -- the socialist party Pasok -- supports the cuts, individual party members came out against them.
Radical leftist party Syriza, bitterly opposed to austerity and closely connected to Greek unions, called on its website for Greeks to demonstrate against the "rape" of democracy and the dashing of the hopes of the people.
Samaras warned that if the measures didn't pass, international funds would not arrive and the nation could plunge into chaos. He pushed for Greece to receive more than the 31.5 billion euros expected in the latest installment "so that there is a significant effect on the real economy."
Greece, and particularly Athens, has seen repeated street demonstrations against the austerity measures imposed on the nation, some of which have turned violent.