22 will now take place without spectators after the Portuguese government announced a partial lockdown on Saturday to fight a surge of COVID-19 infections.
The first MotoGP race in Portugal since 2012, due to take place at the Algarve International Circuit, will now be held behind closed doors due to new measures announced by Prime Minister Antonio Costa, which kick in from Nov. 4.
Around 27,000 fans attended the Formula One Grand Prix in Portugal last week but Costa said the event had not been a success as social distancing was not observed.
"What happened at the Grand Prix is unacceptable and cannot be repeated," he said.
"We have already told the organisers that the MotoGP race will be held without an audience because our inability to organise events of this scale with spectators has been revealed." (Reporting by Richard Martin Editing by Toby Davis)