In August, the King called early elections after the Speaker of the House claimed the government had acted unconstitutionally and was trying to gather power for itself.
But the minister Vuna Fa'otusia said a judicial committee within the Privy Council caused instability by vetting parliamentary bills before they reached the King.
He said the committee, made up of the King's Law Lords, had taken it upon itself to decide what was appropriate for Tonga.
"You see how serious it is. That committee, they are unelected members, and they are the people to consider what is appropriate for Tonga? What is this? Those people...outside of the elected people, outside of parliament, outside of government."
Vuna Fa'otusia said the government had proposed to amend the constitution so cabinet members could become part of the Privy Council, allowing ministers to discuss laws directly with the King.
Photo: Tonga Parliament The Tongan parliament buildings