Update, 1.15pm Wednesday: Authorities have resumed their search for an entangled young southern right whale but have not sighted it today.
An observation plane is circling near Narrawong while crews are also conducting searches from the shore.
"If we are able to locate the whale today, we have our specialist on-water crews in place and ready to launch when conditions permit, and it is safe to do so," incident controller Simon Sealey said.
The whale is grey-coloured and about 10-metres long with rope tied around its tail.
It was last sighted on Tuesday afternoon near the Fitzroy River mouth.
Authorities have asked drones in the area to stay grounded, due to aircraft operating as part of the incident response.
Vessels and aircraft associated with the incident can operate close to the whale. All other vessels and aircraft not involved with the incident must stay 500 metres away
Any members of the public who see the entangled Southern Right Whale can report the sighting directly to our incident management team on 5527 0488.
Tuesday: A juvenile southern right whale has been sighted entangled in rope off Narrawong, triggering an emergency response.
Authorities including the Department of Environment, Land, Water and Planning, Parks Victoria and the Victorian Fisheries Authority have been responding to the entanglement since 9am, Tuesday.
The specialist crews spent the day at Narrawong, near Portland, conducting observations from the ground, air and water to assess the mammal and the entanglement.
It's believed the whale has rope wrapped around its tail.
"The on-water conditions were not suitable to attempt to remove the entanglement safely today," DELWP wrote in a social media post.
Authorities will launch an observation plane on Wednesday morning to confirm the whale's location, and crews will be in place to launch when conditions safely allow.
It follows a humpback whale that became entangled in rope off Portland in 2019. Crews freed the whale after launching a rescue mission.
DELWP's Mandy Watson told The Standard last month that a southern right whale was residing with a calf near Narrawong in a promising sign of calving returning to that part of the coast.
The adult whale was thought to be Yanuk Splash, named by Narrawong primary school students in 2018.
Members of the public who see the entangled whale can report the sighting to the Whale and Dolphin Hotline on 1300 136 017.
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