Four MPs rejoined PASOK on Wednesday, a few weeks after being ejected from the Socialists’ parliamentary group for opposing the latest austerity package, but their return did not disguise the deepening tension in the party.

It was announced that former ministers Costas Skandalidis and Angela Gerekou, along with Michalis Kassis and Yiannis Koutsoukos would cease to be independent MPs. Their return took the number of PASOK lawmakers back up to 28, which is still lower than the 33 the party had after the national elections in June. It also increased the number of deputies in the tripartite coalition to 168, a comfortable majority in the 300-seat House.

Their return came as PASOK heads toward its party congress at the end of the month. Preparations have led to tension within the party. A group of 75 members, including some MPs, issued a statement expressing concern about the way the congress is being planned. Their intervention is seen as casting doubts on Evangelos Venizelos’s leadership.

The tense atmosphere in the party was evident when members faithful to former Prime Minister George Papandreou almost came to blows with Venizelos supporters at PASOK’s headquarters in central Athens on Wednesday over complaints that the congress participants had not been announced yet.

The party could also suffer further damage from the parliamentary inquiry into the Lagarde list.

Police experts informed MPs Wednesday that files containing the names of some 2,000 Greek depositors had been opened on September 30, 2010, hours after the CD with the list was given to then Finance Minister Giorgos Papaconstantinou and that the person opening them had used 28 keywords to search the data, including “George Papandreou,” “Papakonstantinou” and names of other politicians and businessmen.

The inquiry is likely to be extended until the end of March.