Fiji's Energy Minister says Labour's nine cabinet ministers should remember they were elected under the party banner.
Lekh Ram Vayeshnoi, who could face the sack from cabinet for his opposition to the budget, made the comment after Labour ordered all of its MPs to vote against it.
The decision was made at Labour's annual delegates' conference in Nadi at the weekend, attended by only three of its cabinet ministers.
But Mr Vayeshnoi says its cabinet ministers are bound by a collective agreement by the party's top hierarchy to vote against the budget on Wednesday.
He says the party had a right to make a decision, even though six cabinet ministers were absent.
"The Party decides on major policy issues. It cannot agree to the increase of VAT and other taxation measures being imposed on the people of Fiji during this trying time. Above all, the Fiji labour party as a partner in the multi-party cabinet was not consulted on these taxation measures."
Mr Vayeshnoi says those MPs opposing the move could face disciplinary action from Labour's national council.
He claims the Prime Minister deliberately sent some Labour ministers to a trade fair in India so they would be unable to vote.
One of them is Labour's vice president, Krishna Datt, who has questioned Labour's stance on the Budget.
