The Knesset on Monday morning opened the debate for the proposed state budget for 2013 and 2014 in a session expected to last well into the wee hours of Tuesday morning.

MK Nissan Slomiansky (Jewish Home), the head of the Finance Committee, told the plenum the budget attempts to relieve the burden on the lower and middle classes, and pushes the stronger economic classes to shoulder the bulk of the heavier taxes.

The bill, which was approved by the Finance Committee last week, includes cuts to the budgets of the Defense, Education, and Transportation ministries.

If the budget is not passed by the end of the month, the Knesset will automatically be dissolved and new elections will be called.

Earlier this month, Jewish Home leader Naftali Bennett made his party’s support of the budget conditional on the government advancing a bill calling for a national referendum before handing over any Israeli-controlled lands in a future peace agreement with the Palestinians. After Prime Minister Benjamin Netanyahu advanced the referendum bill through the cabinet, passage of the budget seemed set to pass without a glitch.

However, following the cabinet vote on Sunday to gradually release 104 long-term Palestinian prisoners in order to facilitate this week’s resumption of negotiations with the Palestinians, the budget’s fate may be more uncertain. MK Moshe Feiglin (Likud Beytenu) absented himself from the Knesset plenum Monday and called on his colleagues to obstruct the budget’s passage to protest Sunday’s “miserable decision.”

The heads of all Knesset factions will address the plenum over the course of the debate, as will Slomiansky, other committee heads who dealt with aspects of the budget, and opposition leader Shelly Yachimovich (Labor).

Among the changes to the budget that won Finance Committee approval last week was the revocation of an across-the-board 1.5-percent hike in income tax.

Instead, there will be a 1% income tax increase on monthly wages of up to NIS 14,000 ($3,900) and a 1.5% tax on income between NIS 14,000 and NIS 22,000. Salaries above NIS 22,000 a month will be taxed at an additional 2%.

In his opening statement to the Knesset on Monday morning, Yesh Atid Knesset faction chairman and Finance Committee member Ofer Shelah said the budget that must be passed is one “that leaves no choice, born inside an unprecedented fiscal hole.”

Shelah added that within the proposed budget, “the seeds of change have already been planted” in both the Finance Ministry and the Finance Committee. “We approved an unprecedented set of regulations designed to plug the loopholes through which of the upper crust of society escapes taxes.”