Two of three Altona bound lanes on the M80 Ring Road near the Hume Freeway have closed, following a multi-vehicle collision.
The Department of Transport said delays are building rapidly and speeds have been reduced to 40km/h.
Motorists are able to exit via Dalton Road or Edgars Road or detour via Mahoneys Road and Sydney Road, then returning to the M80.
Drivers are under the direction of emergency services and lanes will reopen once it is safe to do so.
Real-time updates are available at traffic.vicroads.vic.gov.au
