The Cook Islands Group for Political Change says the government has no excuse not to reduce the parliamentary term.
The group's spokesperson, Elizabeth Ponga, says an overwhelming majority has signalled the need for this change in last week's referendum which was coincided with the general election.
82.3 percent voted in favour of shortening the term from five to four years.
Mrs Ponga, who was an unsuccessful independent candidate for the Tupapa/Maraerenga seat, says this is the third political reform effected by her group over the past two years.
The group put pressure to abolish both the overseas constituency and the MPs superannuation scheme.
She says the next step for group is to look at reducing the number of seats in the country from the current number of 24.
The clerk of parliament, Nga Valoa, says the change to the term will be passed in the next session of parliament, the timing of which depends on petitions lodged following the final election count.