The National Apprentice Race Series heat at Doomben has been abandoned because of the impacts of coronavirus.
It was felt it would be unfair for apprentices to travel from around Australia to Queensland and risk exposure to the virus.
The $45,000 Benchmark 68 will remain on Wednesday's program as scheduled and will now be conducted under standard conditions.
A Racing Queensland spokesperson said a decision on all future legs of the 2020 Series was expected to be determined later this week by the participating racing authorities.
Queensland leads the series after a win by Adin Thompson in Perth and a third by Dakota Graham in Hobart in the first two heats.
There are two other heats besides Doomben, at Sandown and Murray Bridge, in abeyance.
The series involves apprentices from all states except NSW as well as New Zealand and Singapore.