Greece has responded sharply to apparent pressure from the EU not to pass Wednesday a "humanitarian crisis" law that would provide free electricity and food stamps for the poorest households.
Athens was reacting to an apparent message from Declan Costello, a representative on the European Commission team monitoring Greece, telling the Greek government not to proceed with the vote.
"We would strongly urge having the proper policy consultations first, including consistency with reform efforts," Costello said in the letter quoted in a blog by a reporter from Britain's Channel 4 News.
"There are several issues to be discussed and we need to do them as a coherent and comprehensive package.
"Doing otherwise would be proceeding unilaterally and in a piecemeal manner that is inconsistent with the commitments made, including to the Eurogroup as stated in the February 20 communique," the letter reportedly said.
Greece won a four-month extension to its 240-billion-euro ($255 billion) EU-IMF bailout in February, but has not received the last tranche because Brussels insists on first approving Athens's new reform package.
Costello's message, reportedly written on Tuesday after a meeting of Eurogroup technical experts, also referred to a law that would allow tax arrears to be paid in instalments, and is due to be presented to the Greek parliament on Thursday.
It was not possible to confirm the existence of the letter with the Commission late Tuesday.
The Greek government however reacted sharply to the criticism.
A government source spoke out against "complaints against the humanitarian crisis bill" saying that "if in 2015 in Europe the fight against a humanitarian crisis is considered a unilateral decision, what then remains of European values?"
She said the issue demonstrated "that the technical teams are not able to guarantee implementation of the February 20 agreement."
The humanitarian law is the first by the radical left-wing government of Prime Minister Alexis Tsipras, who came to power in late January, to be presented to the Greek parliament.
Tsipras, who advocates a "political" solution to the Greek crisis, has asked to meet with top European leaders, including German Chancellor Angela Merkel and French President Francois Hollande, on the sidelines of an EU summit in Brussels on Thursday and Friday.
Greek government coffers are almost empty and Tsipras needs further financial assistance for his country, but he also wants to enact social laws that break with the austerity imposed by creditors since 2010.
His government's refusal to fall into line with eurozone partners over its massive bailout has angered member governments, especially powerhouse Germany, but Spain and Portugal as well.