UPDATE: All outbound lanes of the Hume Freeway are now open.
EARLIER: All outbound lanes of the Hume Freeway are closed prior to Donnybrook Road following a collision.
The Department of Transport said motorists should exit northbound lanes of the Hume Freeway at Cooper Street, and use Mickleham Road to the west, or Epping Road to the east.
Motorists can then use Donnybrook Road to rejoin the freeway, the department said.
Emergency services are on site.
Citybound lanes remain open.
Real-time traffic conditions are available at traffic.vicroads.vic.gov.au or via the VicTraffic mobile app. The latest public transport information and network status is available at ptv.vic.gov.au or in the PTV mobile app.