Samoa’s incumbent prime minister suffered a setback in his bid to retain power Friday when a court disqualified one of his party’s candidates over bribery, further boosting his rival’s majority.

The Pacific nation’s caretaker leader Tuilaepa Sailele Malielegaoi has refused to leave office despite narrowly losing an April 9 general election and suffering numerous court defeats in his bid to challenge the outcome.

The latest came on Friday when the Supreme Court overturned the election of Seiuli Ueligitone Seiuli, who had won a seat for Malielegaoi’s Human Rights Protection Party (HRPP).

The court found Seiuli was guilty of bribery after presenting cash to a village meeting last year and ordered a by-election for his seat on a date yet to be determined.

The decision leaves HRPP with 24 seats, while Malielegaoi political foe Fiame Naomi Mata’afa’s FAST Party has 26.

Mata’afa argues she is prime minister-elect and Malielegaoi should stand aside after his 22-year rule, and allow her to become the nation’s first female prime minister.

Mata’afa was sworn in last month in a tent on the lawn of parliament after loyalists to the previous government locked the doors of the building in a bid to stop her from assuming power.

A legal challenge to the swearing in is expected to be heard next week.