Sebastien Ogier and his co-driver Julien Ingrassia contacted the organisers after the recce, concerned by the barriers on a new stage included for the first time this season.
There were five points of concern on the Tergu-Osilo test which runs tomorrow.
Ogier said: "We made a report to the FIA directly, asking to protect the barriers. Already, there were too many accidents like this, so something had to be done.
"I don't want to race in the condition like this. OK, they were not exactly on the line, and if you stay on the road then you can have no problem but you never know what can happen."
Ingrassia is a member of the WRC's safety working group and he emailed his fellow working group members with their concerns.
"I noted the places where they are very dangerous and for three points [in the stage] it was very bad, so this is why I made the email to them," said Ingrassia.
"We have spoken about this with huge importance since some very bad accidents in the last 15 months. This is the black point of the moment and I was really upset and angry that nothing has been done on a new stage like this."
Event director Antonio Turitto said the crews' concerns would be addressed.
"We know about these places," he said. "And we will put the straw bales at the end of the barriers. The only reason we didn't put the bales there during the recce is in case they get stolen. But we will put them there before the cars go through."
- Julien Ingrassia