General manager David Mills said COVID-19 concerns would limit international racers while Western Australia's border restrictions - tipped to end on February 5 - could hinder teams from making a trip across the Nullarbor.

The three-night showcase has attracted more than 100 cars in recent times.

Mills is still bullish of a bumper field despite obstacles for the January 21-23 event.

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"If we get over 72, the format works to stay the same, so that is the threshold we're looking at, at the moment," he told The Standard.

"We have an alternate format there if it is under 72 but we're hoping we don't have to invoke that at all and we can do what we do and split the field into two nights.

"If we could get to 80 it would be really nice, and have 40 each qualifying night, I think that would be a good set-up and it's a good number to work with for the third and final night too."

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American Carson Macedo is already in Australia - he competed at Premier Speedway on New Year's Day - but Mills said he might have to fly his country's flag.

"I think at this late stage I wouldn't be expecting too many more internationals," he said.

"I think guys who might have come in previous years, when the border restrictions were in place and it was looking difficult, they have probably taken the opportunity to get it right at the Chile Bowl or prepare for the new (World of Outlaws') season.

"I'd be pleasantly surprised if an entry came through with another international name on it."

American-based Australian duo Brooke Tatnell and Kerry Madsen - past classic winners and strong supporters of their home country's biggest meeting - are unlikely to make the trip.

Mills said Tatnell was eyeing the Chile Bowl. WA team Monte Motortsport, with Warrnambool's James McFadden in the hotseat - will ensure some Sandgroper representation.