Warrnambool Racing Club announced on Friday it was making preparations to host the event crowd-free if needed as concerns spread about the impact of coronavirus.

It came after the Melbourne Grand Prix was canned just hours before the first practice session was scheduled at Albert Park.

Prime Minister Scott Morrison later confirmed all mass gatherings attended by more than 500 people - including football games, concerts and conferences will be cancelled from Monday.

Warrnambool Racing Club chief executive officer Tom O'Connor said the club was concerned, but the racing industry had since "pulled together a crisis management team to look closely at the situation which is changing hourly".

Last year's May Racing Carnival carnival saw a direct economic impact of more than $13 million, and brought close to 30,000 spectators to the racecourse, of which more than 76 per cent were from outside the Warrnambool region.

Following the successful three days, Warrnambool City Council's visitor economy manager David McMahon said the racing carnival was the city's "single biggest event in terms of economic impact and city branding".

A Warrnambool accommodation provider, who wished to remain anonymous, said the hotel was already booked out for the May Races period.

"It's our best time of the year," they said.

"We've had rooms booked since May last year with some people who have been coming for 20-odd years.

"None of these people will come if they can't attend the race meet. It would be devastating for us, other hotels and motels, as well as restaurants, pubs and shops."

Warrnambool's Cally Hotel manager Lucas Reid said cancelling the event would have a significant impact on the establishment, which hosts May Races after-parties in a marquee.

"May Races is a significant week for us with over 1400 through the business every day," he said.

"If there's no customers then there is no work for our casual staff that would normally get employed during that week. It would affect our live music bookings and things like that, it would have a real flow on effect.

"If it happens then that is beyond our control but we have our own contingencies in plan so we know what to do going forward."

Across the region, some events involving mass gatherings or international travel have been cancelled.

Warrnambool's St Joseph's Primary School principal Michael Gray said the annual school fair, which usually draws crowds in the thousands, was cancelled on Friday afternoon.

He said the fair was supposed to be held at the school on March 28 but would now be postponed until a later date.

"With a big crowd expected to attend, we've decided to postpone the event for the health, safety and well-being of the community," he said.

"It is just a precaution and the school system is monitoring developments very closely."

Emmanuel College principal Peter Morgan said the school had cancelled all overseas trips for the year, including student camps to France, Nepal and East Timor.

"Those cancellations have been put in place at the direction of higher authority," he said.

"We have communicated that information with our parents, and are working through the process of what that means for our students."

Mr Morgan said the school "did not at this point have any directive not to host any school events".

"We have a team of people within our school that continue to meet regularly to discuss future events. Every school has events happening all the time and we will have to look at each one on a case-by-case basis," he said.

Three Hamilton schools have also cancelled all international school trips until further notice, and about a dozen south-west students expected to compete in the 2020 State Track and Field Championships this weekend were told not to attend the Melbourne event.

A media statement released by Little Athletics on Friday said the decision was made in line with other sports and public events with regards to mass gatherings.

"While other sports can conduct their competitions in the absence of crowds, Little Athletics, with its requirement for parental oversight and volunteers, cannot proceed," the statement said.

Meanwhile, the future of some major south-west events remains unsure.

The Koroit Irish Festival committee will meet in two weeks to discuss the event which is set to take place the weekend before the May Racing Carnival.

A spokesman said the committee was constantly monitoring neighbouring events, such as May Races, as they unfold.

The spokesman said the festival had doubled its online ticket sales compared to this time last year but that the "safety of the community was paramount".

"We want the event to go ahead but we will also make sure we make the right decision so that no one is adversely affected," he said.

"We want to play our part in making sure everyone is safe, fit and well."

The spokesman said the community and ticket holders would be updated when necessary.

Warrnambool RSL president John Miles said the Anzac Day service would be going ahead with or without a crowd.

"We will be hosting a service on April 25 but whether or not it will be open to the public, I cannot say at this stage," he said.

South West Healthcare last week revealed less than 20 people had been tested for the virus and no one had returned a positive result.

A spokesman said the public would be notified if any positive tests were returned. He stressed there was no need for alarm.

He said there had been at least 2000 negative tests returned across the state after cases of the virus were suspected.

In Portland, one person has been tested for the virus at Portland District Health (PDH) following international travel and is currently isolated at home awaiting results.

Infection control coordinator Loren Drought said PDH had established a fever room and was following Department of Health testing requirements and establishing separate fever or respiratory presentation rooms, in case of a local coronavirus outbreak.

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