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.