These include extending the term of parliament, changing the definition of a Vanuatu citizen, and increasing the size of Cabinet by nearly a third.
A second session of parliament on Friday was adjourned because of a lack of MPs.
Prime Minister Bob Loughman wants to push through at least 15 constitutional changes which the opposition and some MPs in both his coalition and his own Vanuaaku Pati oppose.
On Friday there were only 31 of the 52 MPs present.
For a constitutional change a minimum of 34 MPs is needed.
On Thursday lawyers in Port Vila published a statement strongly criticising one of the planned constitutional amendments.
They say the government's plan to put the chief justice's position on a fixed-term contract undermines the credibility of that judicial office.
The adjournment of the Vanuatu parliament over the seven days to Friday cost the country's taxpayers more than 3.7 million Vatu or $US32,000 dollars.
This is because MPs and cabinet ministers each get daily allowances when the parliament is in session.
But on Friday a week ago the session was adjourned because many MPs had boycotted over government plans to push through sweeping constitutional changes.
Ati George Sokomanu, who was the country's first president is calling for more communication among the leaders and respect for the procedures required under the constitution to avoid wasting taxpayers' money.