Councils do not have the money or expertise to operate a system banning polluting vehicles from city centres, a Scottish Parliament committee fears.
The SNP has pledged to introduce low emission zones in Scotland’s four largest cities, including Dundee.
But a report from MSPs warns the timescale for roll-out is too ambitious, with confusion likely because local authorities will not be in a position to enforce the zones until years after their introduction.
The Air Quality Inquiry, which is published by Holyrood’s environment committee on Wednesday, also demanded more clarity from ministers on the phasing out of diesel and petrol cars by 2032.
The report said: “The committee, while fully supporting the creation of low emission zones, has some concerns over the tight timescale around their introduction and whether the relevant local authorities have the necessary resources – both technical and financial – for them to be fully operational.
“The committee notes that even if they are in place by the deadlines set by the Scottish Government, they will not be enforced for a number of years.
“This may cause some confusion to those using the LEZs, particularly bus operators and small freight firms.”
All vehicles apart from those with the cleanest engines will be punished from going in LEZs in city centres.
Ministers propose that only diesel cars that meet Euro 6 emission standards, which were set by the EU in 2014, would face no restrictions for entering an LEZ.
For petrol cars the minimum standard is Euro 4, which came into force in 2005.
Vehicles that are older than those dates may not meet the required standards.
A Scottish Government spokesperson said: “We are committed to working with local authorities to introduce low emission zones (LEZ) consistent with national standards.
“We believe that local authorities should be ambitious in their LEZ designs and consider all vehicles for inclusion.
“Lead-in times for LEZs are an essential requirement in the design as they allow residents and businesses time to prepare for the new forthcoming emission standards, prior to enforcement starting.
“We have also introduced an interest free loan scheme to support low emission vehicle ownership, and a £14.5m green bus fund which has seen the introduction of 300 low emission buses to the Scottish fleet.”