Marsters was born on Palmerston Island and educated at Nikao and Avarua Primary Schools before attending Avele College in Samoa[1] and Grimsby Institute of Technology in the United Kingdom.

Marsters served as Minister of Works in the Cabinet of Sir Geoffrey Henry, but resigned his position in 1997 in protest at budget cuts.

[7] In August 2005, Marurai sacked Cook Islands Party leader Sir Geoffrey Henry from Cabinet,[8] causing the CIP to reconsider its role in government.

[9] The retirement of Sir Geoffrey Henry in 2006 led to a leadership election, which saw Marsters replaced as Deputy leader by Tupou Faireka.

In June 2016, he made a rare intervention as Queen's Representative, ruling that Parliament had been properly adjourned and that therefore a purported opposition vote of no-confidence ousting the government was of no effect.