Cal Crutchlow described track conditions on the final corner of the Estoril circuit in MotoGP practice as a "joke," and hopes the issue of the surface retaining water can be resolved before the race.
Tech 3 Yamaha rider Crutchlow was third quickest in Portugal on Friday, but led criticism of the surface at the final turn.
"I think it was a bit of a nightmare for everyone," Crutchlow told the official MotoGP website. "The last corner is a joke. There are wet patches all the way around it. It hasn't rained since four o'clock in the morning, and it's still wet now.
"We need to go to the safety commission now and see if we can get something done about it, because the Tarmac's just holding the water. We need to see if we can dry it, because if it rains in the middle of Saturday night, it will still be wet for the race, which is not good.
"The problem is you can't see it because it's so black, the tarmac, that you can't even see if it's got water on it."
Crutchlow acknowledged that the whole field was equally disadvantaged, but said his concern was simply the safety aspect.
"It's the same conditions for everyone, but it's just risks that we don't really need," he said.
Honda rider Dani Pedrosa agreed that the track surface, particularly at the last bend, had been a significant issue on Friday.
"In the first session we were almost unable to ride and in the afternoon it was difficult because the track conditions were poor, it was very slippery, we had no grip in the front or rear and it was kind of hard to get feedback from the bike because the tires were just sliding," said Pedrosa.
"Water is holding on the new asphalt, so it's necessary to change the line. It would be good if it doesn't rain anymore and if they could dry this area up in some way because in the last corner especially, it's very damp.
"I hope the track gets better tomorrow on the grip level, so we can start working hard on the suspension."