West Bengal Finance Minister Amit Mitra on Monday alleged that the GST council has turned majoritarian and decisions were no longer taken on the basis of a consensus as originally envisaged.
He also said voices of the Group of Ministers in the council remained unheard.
Mr Mitra said that he had tried his best to "raise objections" during the 44th GST Council meeting on Saturday, but the virtual link was snapped at a "critical time".
The veteran economist demanded a probe into how and who had "muted" his microphone when the meeting was in progress.
"Authoritarianism and majoritarianism have taken over the GST Council... It's most unfortunate," he told reporters.
Mr Mitra had also written a letter to Union Finance Minister Nirmala Sitharaman after the meeting to record his "dissent" against decisions of the council.
"I was heard repeatedly in the meeting. But during the concluding part, I kept on raising my hand and you could see me... All (other) microphones were unmuted by the Centre's web management team.
"My microphone was muted and I could see it... I am not a fool. Please investigate and let me know. Why was my microphone muted at a critical time when I wanted to put across my dissent? I am giving the benefit of doubt," he said on Monday.
Stressing that he shared a "very cordial relationship" with Ms Sitharaman, Mr Mitra said he is yet to receive a reply from her.
Mr Mitra had Saturday termed the GST Council's decision not to reduce taxes on COVID-19 vaccines as "anti-people".
The council has slashed tax rates on coronavirus drugs such as Remdesivir and Tocilizumab as well as on medical oxygen and oxygen concentrators, but ignored demands for a reduction in taxes on vaccines.