Nottingham Forest have filed a complaint with England's professional referees body (PGMOL) over the officiating in their 2-1 Premier League defeat at Manchester City on Saturday, British media reported.
The club contacted PGMOL on Monday to request the VAR audio from the match, the reports said.
Forest manager Sean Dyche said after the match that Rayan Cherki’s 83rd-minute winner should have been disallowed for a foul on Morgan Gibbs-White in the build-up.
He also argued that City defender Ruben Dias should have been given a second yellow for a foul on Igor Jesus after the break.
Forest, who are one spot above the relegation zone in 17th, did not immediately respond to a request for comment outside normal UK business hours.