Businesses have raised fears over the introduction of the proposed workplace parking levy.
The move would allow local authorities to introduce a levy on parking, if they chose to do so, as part of measures to reduce congestion and tackle air pollution.
It is currently under consideration by Holyrood's Rural Economy and Connectivity Committee, having been initially agreed under the Budget deal reached between the Scottish Government and the Scottish Greens earlier this year.
Ahead of the committee meeting on Wednesday, insurance company Aviva, in its submission, suggested that the levy could ultimately become a tax on employees.
The submission read: "However much it is presented as an environmentally-friendly measure, the reality is the levy is a straightforward tax on business and, potentially, their employees.
"This new tax would be particularly hard-hitting for businesses that chose to locate in rural locations; where it is already more challenging to recruit and retain staff, the introduction of the levy will simply make this harder."
In its submission to the committee, the Scottish Trades Unions Congress (STUC) also urged MSPs to reject the proposal.
Their submission stated that "while the levy will be raised on employers, it is likely to be passed on to employees", going on to suggest that the levy would be "difficult to justify when in-work poverty is rising quickly and wages across the board have stagnated".
The Educational Institute of Scotland (EIS) teachers' union also indicated its opposition to the measure, saying: "The EIS believes that the workplace parking levy would disadvantage teachers and become an additional tax for many that have no alternative but to drive to work."
Paths For All, a charity that promotes walking, outlined its support for the measure in its submission.
It read: "The proposed workplace parking levy is a progressive intervention and entirely in keeping with the Government's ambition to reduce greenhouse gas emissions, improve health and reduce air pollution."
Scottish Conservative finance secretary Murdo Fraser called for the proposal to be "scrapped immediately".
"The SNP cannot possibly ignore this criticism of the car park tax any longer," he said.
"So far it has completely dismissed the input of workers, employers and even the police on this hated scheme.
"Now we see social workers, insurance companies and retail organisations pointing out the very considerable flaws within the proposals.
"This extra tax won't cut congestion and won't change anyone's commuting habits.
"Instead, it will hit workers and businesses for hundreds of pounds a year, and make life even harder for people who are just trying to get by.
"The car park tax has to be scrapped immediately."
A Scottish Government spokesman said: "The Scottish Greens' amendment to the Transport Bill gives local authorities the power to introduce a workplace parking levy based on their circumstances should they choose to do so.
"Schemes would be tailored to local needs and councils would have to consult and carry out impact assessments on their proposals as well as create a local transport strategy before introduction."
He added: "The Transport Bill provisions are for a national exemption that will apply to NHS buildings. Hospices will also be exempt from the levy, as will Blue Badge holders.
"In addition to the exemptions already proposed, the provisions enable local authorities to consider further local exemptions and they are also required to consult on the specifics of any scheme prior to implementation."