Girlfriend kidnaps partner's son: police

(AAP) - A woman has kidnapped a seven-year-old boy from Ballarat after stabbing the child's father whom she met on an internet dating site, police allege.

The woman, 37-year-old Danielle Boundy, is believed to have fled with the boy, namedSteven, after an argument with his father.

Police have grave fears for the boy and believe Ms Boundy may be headed toQueensland, where she has contacts, Detective Sergeant Gerry Richardson told AAP.

Boundy and the boy's father had been in a violent relationship for two months and had argued at a petrol station in Ballarat, west of Melbourne, at 4pm (AEST)Wednesday, police said.

Steven's father, a 44-year-old Winchelsea man, reported the pair missing to policeon Wednesday night.

Ms Boundy phoned Steven's mother at her Corio home at about 1am advising her she would drop him off at the Winchelsea police station on Thursday morning, but shefailed to attend.

"This is the result of a violent domestic involving a knife," Det Sgt Richardsontold AAP.

"She has then taken off with his son.

"Initially, there was no concern but the return this morning never happened.

"We have serious concerns for the welfare of the child and Miss Boundy ... this is not just a missing person case." The boy's father suffered serious eye injuries after allegedly being stabbed by MsBoundy, whom he met on an internet dating site.

Ms Boundy has a history of mental health problems and has been hospitalised before,police said.

She is believed to be travelling in a green 2000 model Mitsubishi Magna sedan,registration QKU 463.