MPs are to begin debating on Tuesday the multi-bill containing all the structural reforms being demanded of Greece by its lenders as well as the 13.5 billion euros in spending cuts and tax hikes that the government will have to implement over the next two years.

Lawmakers are due to vote on the draft law late on Wednesday, ahead of a vote on the 2013 national budget late on Sunday.

Although it is expected that the government will get the majority it needs for the measures to pass, there are some tense moments ahead for Prime Minister Antonis Samaras.

Samaras suffered a scare on Monday when Justice Minister Antonis Roupakiotis, who is aligned with junior coalition partner Democratic Left (DIMAR), initially refused to sign the multi-bill.

Roupakiotis held lengthy talks with DIMAR leader Fotis Kouvelis before softening his stance and signing the legislations, which runs to more than 500 pages and was submitted to Parliament late on Monday.

Kouvelis, whose party is opposed to the labor reforms included in the bill, held a meeting of DIMAR’s central committee late on Monday to decide what the party’s position should be during the two upcoming votes.

The veteran leftist proposed that his party’s lawmakers vote “present” on Wednesday and in favor of the budget on Sunday. This would make it easier for the government to get a majority and would allow DIMAR to continue as part of the coalition as it would not have oppose legislation.

Kouvelis’s proposal received overwhelming support from members of the party’s central committee.

DIMAR has 16 MPs, so it would take a mutiny from several PASOK and New Democracy members for the measures to be rejected.

Two of PASOK’s 32 deputies have said they will not approve the package, the latest being Mimis Androulakis, who made his objections known on Monday.

New Democracy has 127 lawmakers, who Samaras spoke to on Sunday. So far, there are no indications if any of them will oppose the measures.

This means that in the best case scenario, the multi-bill will receive 157 votes of support on Wednesday, leaving only Sunday’s budget vote for Samaras to worry about ahead of a Eurogroup meeting on Monday, when Greece expects its next loan tranche of 31.5 billion euros to be approved.