A man who dived by night into water hazards at dozens of South Korean golf courses to collect lost balls has been arrested for theft, police said Friday.

The man identified only as Lee, a 42-year-old former golf club employee, is accused of stealing some 26,000 lost balls worth 13 million won (S$15,600), police said.

Wearing a diving suit and an oxygen tank, Lee since June last year had searched water hazards by night to retrieve the balls.

Police said he either worked alone or teamed up with his niece or a friend, who were arrested in September last year for stealing some 22,000 balls.

The trio sold the balls to training ranges for 500 won each.