Two Southern Right whales have spent the week swimming between Secret Harbour and Singleton beaches, putting on a show for locals.
Matthew Swan from the Department of Biodiversity, Conservation and Attractions said the calf is only about a week old.
"It's fairly common to see Southern Right whales on our coastline at this time of the year...the females particularly will move up into the sheltered waters where they will give birth to their young," Mr Swan said.
"There's no doubt this calf has been born in our waters and it has happened in the last week or so."
Mr Swan said they had received reports of a sick whale close to shore but it was actually the whale in labour.
"We have had reports of people saying there is a whale in distress or there's something wrong with a whale just off the coastline, but it is very common for them to come and sit anywhere from 50 to 100 metres off the beach and it's a term we call 'logging'."
"They just look like big logs that sit in the waves or just behind the breakers and from there one day we go from having one whale to suddenly having two."
Mr Swan said the whales could hang around for sometime.
"Once mum feels confident that her calf is ready to go and has enough body weight she'll head south again."
Locals are being urged to stay at least 100 metres away from the whales.
Peel Thunder's Bo Allan becomes an Eagle
Christmas on the Murray 2024
Man charged over Henderson hit-and-run crash
Manslaughter charges dropped against man accused of Mandurah boat tragedy
Rockingham boy critically injured in Bali quad bike crash
Christmas cheers returns to Mandurah
City of Mandurah launches new community safety strategy
Winners announced for the 2024 Alcoa Peel Business Excellence Awards
Mandurah: Three girls charged with aggravated armed robbery