President Maithripala Sirisena and Opposition Leader Mahinda Rajapaksa will today chair an opposition MP group meeting to discuss the third reading vote on the budget.
The SLFP's position on the third reading vote is likely to be decided at the meeting.
Speaking to media, SLFP MP Shantha Bandara, a Sirisena supporter, said the UPFA group supporting President Sirisena vehemently opposed the budget.
"Therefore, we will not support the budget under any circumstances," he added.
However, the SLFP is still undecided on whether to vote against the budget or to abstain from voting.
The SLFP's decision to abstain from voting at the second reading vote became a point of contention between the SLPP and the SLFP. The SLPP made it clear that the future of the ongoing discussions between the SLFP and the SLPP would be determined by the SLFP's stance on the budget at the third reading vote.
However, the ruling party secured the support of 119 MPs in the House at the second reading vote last month.