Prime Minister Lucas Papademos will speak to the leaders of the three parties that make up his coalition government on Friday or Saturday, sources said on Thursday, after rebel MPs blocked the liberalization of pharmacy opening hours, which is one of many reforms that Greece has to pass to qualify for further loans from the European Union and International Monetary Fund.

The resistance shown by the deputies, mostly from PASOK, came a few hours before Finance Minister Evangelos Venizelos wrapped up two days of talks with representatives of Greece’s lenders, known as the troika, who are in Athens for their latest inspection.

Sources suggested that Papademos was disappointed by the MPs’ reactions and would make it clear to PASOK chief George Papandreou, New Democracy leader Antonis Samaras and Popular Orthodox Rally (LAOS) president Giorgos Karatzaferis that all three parties will have to get squarely behind the reform legislation that needs to be passed before the premier heads for an EU leaders’ summit on January 30.

Article 29 of the so-called multi-bill, which contained legislation aimed at opening up several closed professions, received only 101 votes in the 300-seat Parliament. This means that the draft law on pharmacy opening hours will have to be changed and resubmitted to the House. Nine PASOK MPs voted against the article, while another 30 voted “present.” New Democracy deputies also tested the coalition government’s cohesion by abstaining on several articles.

“The whole political system has to show absolute responsibility because it is clear that whatever happens over the next few days will affect the country’s course for years to come,” said government spokesman Pantelis Kapsis, who angered some lawmakers by suggesting that the rebel MPs had been defending the vested interests of certain professions rather than the greater interests of the public.

The political turbulence came as talks between Greece and the troika continue in a bid to agree on what new measures Athens needs to take to receive further funding. Troika officials are due to meet with government officials on Thursday and Friday to discuss structural reforms, fiscal measures and potential changes to labor and pension rights.

The measures will have to include about 2 billion euros that Greece needs to raise as a result of the 2011 public deficit missing its target and rising to 9.8 percent of gross domestic product.

Papademos was expected to meet with cabinet ministers directly involved in negotiations with the troika on Thursday afternoon.