The Red Bull Formula One employee who accused team boss Christian Horner of inappropriate behaviour has lodged an appeal after her complaint was dismissed, the BBC and the PA news agency reported.
The move is likely to keep the subject as a major talking point in Formula One and continue to cast a shadow over the season.
The unidentified woman was suspended last week after an investigation carried out by a senior independent lawyer, who has also not been named, cleared Horner.
The 50-year-old team boss had denied the unspecified accusations against him.
There was no immediate confirmation from Red Bull GmbH, the Formula One champions' Austria-based parent company.
Red Bull GmbH said in a brief statement on Feb. 28, before the start of the season, that the complainant had a right of appeal after the grievance was dismissed.
The energy drink company also said it was confident the investigation had been "fair, rigorous and impartial," but there have been calls for more transparency with no details published.
Horner faced a barrage of questions at last week's Saudi Arabian Grand Prix and can expect more when the circus arrives in Australia next week.
Horner has repeatedly called for the focus to be turned back on racing.
Red Bull have started the year in dominant fashion with two one-two wins led by triple champion Max Verstappen, whose future with the team has become increasingly uncertain due to the off-track events.
Verstappen's father, Jos, said after the opening Bahrain Grand Prix that the team risked being torn apart if Horner stayed in charge.
The Dutch 26-year-old driver has also indicated the continued presence at the team of 80-year-old Red Bull consultant Helmut Marko was a key to him staying after the Austrian feared he would be dismissed.