On Tuesday night parliament voted to suspend the 22 opposition MPs for two sittings, over its boycott of the first sitting last week.
Opposition leader Ralph Regenvanu said the vote by the government members was an outrage.
He said the first sitting had been boycotted many times in the past.
"Boycotting the first sitting of a session is a parliamentary practice in Vanuatu that has been going for 40 years.
"It is disappointing that this in the 40th year of Vanuatu's independence when we have a theme of maturity, that particular parliamentary procedure which has been used and is a part of the culture of the Vanuatu parliament has now been turned into something that is able to be penalised by parliament."
Mr Reganvanu said he believed the government had used its majority to avoid examination of its financial plans.
"The government bills will now be passed without scrutiny.
"There's a Supplementary Budget of over one billion vatu which will not be scrutinised in parliament as to how that money is to be spent," the Opposition Leader said.
Mr Reganvanu said the Opposition had over 10 written questions to ask of ministers and had prepared a motion to cut the salaries of leaders in half.
"It is the view of the Opposition that the reason the boycott resulted in a suspension...was so that motion could not be discussed."
He said the idea was to take pay cuts in solidarity with those who had suffered economically through Covid-19 restrictions.
Mr Reganvanu said the opposition will take an urgent constitutional challenge to the Supreme Court.