SINGAPORE, MAY 26 (AP/UNB) - Voters have dealt Singapore's ruling People's Action Party its third electoral setback in a year, allowing the opposition to hold onto a Parliament seat in a by-election.

Election officials say Workers' Party candidate Png Eng Huat won 62 percent of about 21,700 votes cast in Hougang district. PAP candidate Desmond Choo received 38 percent.

The government called a by-election after the Workers' Party expelled lawmaker Yaw Shin Leong when he refused to explain allegations of personal indiscretions.

Choo lost to Yaw during a general election last May in which the PAP received its lowest total vote since independence in 1965.

The PAP controls 81 of 87 parliamentary seats, with the Workers' Party holding the other six.