Good Samaritan's 'fatherly instincts' helped in rescue of toddler snatched on San Francisco street

Good Samaritans stopped the attempted kidnapping of a two-year-old boy from a busy San Francisco street, police said today.

A well-known Australian disc jockey, Roscoe Bradley Holyoake, 34, from Perth, was arrested over the incident. 

The toddler was holding his mother's hand while they walked in the Castro neighbourhood when the boy was snatched, San Francisco police said. 

They added that the suspect ran for about half a block with the mother and several bystanders in pursuit. 

The bystanders grabbed and held him until officers arrived.

One of those who grabbed the man, Adam Walker, said that adrenaline and "probably a little bit of fatherly instincts" helped him react.

Holyoake appeared briefly in court today and was ordered to return on Friday NZT to enter a plea.

His attorney Steve Olmo told media outside court that Holyoake doesn't have a criminal record and was in San Francisco on business.

Holyoake remained in San Francisco County Jail on $US500,000 bail.