The Greek parliament overwhelmingly adopted a "humanitarian crisis" bill on Wednesday aimed at helping its poorest people, ignoring apparent pressure from the European Union to halt the legislation.

The Greek parliament overwhelmingly adopted a "humanitarian crisis" bill on Wednesday aimed at helping its poorest people, ignoring apparent pressure from the European Union to halt the legislation.

This first package of social measures put forward by Prime Minister Alexis Tsipras' radical left-wing government drew support across the board in parliament, including from the conservative, former ruling New Democracy party.

The bill had prompted a request from Declan Costello, a representative on the European Commission team monitoring heavily-indebted Greece, telling the government to stall its vote on what Brussels called "unilateral" measures.

Tsipras was defiant ahead of the vote in parliament, saying: "Some technocrats are trying to scare us with ultimatums."

In the latest skirmish between the new Greek government and its international creditors, Athens lashed out at the request saying the Commission's move amounted to a "veto" of the bill and added to the "pressure" on Greece.

However, the EU's economic affairs commissioner Pierre Moscovici denied there had been a veto of the anti-poverty bill, which is to provide free electricity and food stamps for the poorest households that were among the ruling Syriza party's key election pledges when they swept to power in January.

"We fully support the objective of helping the most vulnerable and there is absolutely no question of a so-called veto of the humanitarian crisis law," Moscovici told reporters.

Greece said the Commission was already aware of the legislation, which it claimed was mentioned in the February 20 agreement with European Union and International Monetary Fund creditors to extend Greece's 240-billion-euro ($255 billion) bailout.

"The government has committed to adopting measures to tackle the humanitarian crisis... the measures have a relatively low cost," Greek government spokesman Gabriel Sakellaridis told Skai TV, which valued the cost of the bill at 200 million euros.

The row over the legislation was sparked when a copy of an alleged letter from Costello appeared online.

"We would strongly urge having the proper policy consultations first, including consistency with reform efforts," Costello wrote 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.

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 EU powerhouse Germany, but Spain and Portugal as well.

The Greek legislation calls for households that were cut off because they could not pay their bills to be given a capped amount of free electricity.

Up to 30,000 households would also get a housing allowance and 300,000 people would receive food subsidies.