About 12.30am on Saturday, January 17, the 10 youths were walking along Highbury Road near Lincoln Street when up to seven men got out of a blue sedan and attacked them.

One teen was knifed in the chest. Another was pushed off his bicycle and had his mobile phone stolen as he tried to ring 000 for help.

Their attackers are believed to be aged from 18 to 20.

Nunawading police's Detective Senior Constable Paul Scarlett said two motorcyclists, who were seen in the area around the time of the unprovoked assault, might be able to help police with their inquiries.

Information to Crime Stoppers 1800333000.