Albert Nicholas, who defected from the Cook Islands Democrats to join the governing Cook Islands Party earlier this month, has been made internal affairs minister.
He will also be responsible for the ombudsman, youth and sports, and the market, Punanga Nui.
The former internal affairs minister Nandi Glassie has been made justice minister.
The Cook Islands News reports the prime minister Henry Puna suggesting next week's by-election in Aitutaki could also affect the cabinet line up.
Mr Puna says Aitutaki deserves a minister and that is a decision to be addressed after polling day.