While visitor numbers plummeted across Victoria in the past three months, Warrnambool City Council predicted the whales' arrival would fuel a tourist boom for the south-west.

The council's tourism services manager Peter Abbott said the whale watching season had started later than past years.

"I was hoping they would come in time for the (July) school holidays," he said.

"The lack of whales well into June is a concern to the tourism industry as this assists in developing off peak tourism spending.

"But now they have arrived, it's fantastic."

The Department of Sustainability and Environment had reported humpback and southern right whale sightings from Geelong to Portland.

On Saturday, a southern right whale and two dolphins entertained visitors at Warrnambool's Logans Beach whale viewing platform.

Mr Abbott said people were coming from across Victoria to see the city's whales.

"We do have a few international visitors, but they aren't coming to Warrnambool specifically to see the whales," he said.

Portland Visitor Information Centre's Brooke King said southern right and humpback whales were also swimming close to the port's shores.

"We had two southern rights stay in the bay for the whole day the other day," she said.

Whales were sighted off Cape Nelson, Cape Bridgewater and the Lee Breakwater. Port Campbell and Port Fairy also had confirmed sightings.