Three men, aged 38, 42 and 30 and a 39-year-old woman were arrested in the Wodonga area in northeast Victoria as part of an investigation, involving two police task forces and the local crime investigation unit.
All three men arrested are members of the Finks bikie gang, police say.
Victoria Police executed warrants for arrest after they searched a number of properties following a series of violent incidents in the past fortnight.
A fight broke out on June 1 after a 30-year-old Finks gang member went to the home of a 28-year-old man, who police believe struck the man with a blunt object.
"The 30-year-old man left the property and later presented at hospital with a serious head injury," police said in a statement.
"He was subsequently arrested by police on Wednesday, June 7 and charged with aggravated burglary, extortion, burglary and committing an indictable offence whilst on bail."
Five days later police allege two men bashed the 28-year-old with a metal bar outside his home, leaving him with facial injuries.
He was treated for his injuries at a hospital.
The investigation is ongoing.
