A man is critical and a woman is in serious condition after a stabbing on board a bus in Melbourne’s east.

According to police, the incident began when two men and a woman were arguing on a Wantirna South-bound bus at Rowville shortly after midnight.

One of the men then allegedly pulled out a knife and slashed the other man and the woman in the face and upper body area.

The man, a 59-year-old from Scoresby, is in critical condition while the woman, a 53-year-old from Ferntree Gully, is in serious condition.

Police alleged the trio are not known to each other.

Officers rushed to the scene and, with the help of the dog squad, searched the area but could not find the third man.

Several hours later, police patrolling the Knoxfield area found a man matching the description and arrested him.

The man, a 36-year-old from Melbourne, will be questioned by police later today.

Any witnesses or anyone with vision of the incident is urged to contact Crime Stoppers.