Manila - Philippine police said on Friday a sister of boxing hero Manny Pacquiao was involved in running an illegal gambling racket, after detaining 25 people in a raid on her home.

A police vice squad detained the suspects and seized evidence, including gambling materials and cash, in Thursday's raid on the home of Pacquiao's elder sister, Isidra Paglinawan, said Chief Inspector Leo Sua.

Pacquiao, the seven-time world champion who was elected to a seat in the Philippine parliament this year, personally watched as police searched the house, but vowed not to interfere.

A lower court in the southern port of General Santos ordered the raid as part of a police crackdown against an illegal numbers game, locally called "masiao", but the 34-year-old sister was not at home, Sua told reporters.

He said the detained people were bet collectors for the illegal numbers racket, in which bettors place wagers on the last two digits of the winning ticket of the Philippine lottery.

Police seized 33 000 pesos in suspected bets, said Sua, who led the raid. He said police would ask state prosecutors to file illegal gambling charges in court against Paglinawan and the 25 other suspects.

Sua said police were searching for Paglinawan.

Pacquiao told reporters Friday he was attending his father's birthday party when police raided the sibling's house next door.

He said he would ask the police to investigate whether his sister was indeed a "masiao" operator.

"I will not interfere. Let the law take its course," boxing's "pound-for-pound" king said.

Betting in an illegal numbers game, or allowing one's property to be used in its operation, is punishable by up to six years in prison.

Working for an illegal gambling operation, or actually running it, has penalties of between eight and 20 years in prison.

The well-appointed houses of Pacquiao's parents and sisters are tourist attractions in the otherwise depressed General Santos district of San Isidro, where Pacquiao grew up in poverty.

The sister sought by police and her husband have no known permanent jobs.