Living Streets Edinburgh said that might encourage drivers of non-compliant vehicles to enter the city centre zone by avoiding major roads in an attempt to evade detection, increasing pollution in residential areas.
The group expressed “serious concerns” that only 16 of the 48 entry points will have sites for automatic number plate recognition (ANPR) cameras, with the rest of the zone patrolled by a mobile camera unit.
Only vehicles with the cleanest petrol and diesel engines will be permitted in the zone when it is launched next spring, followed by enforcement from 2024 after a two-year grace period.
Motorists with diesel cars and other vehicles made before 2015 and petrol vehicles made before 2006 will be fined if they are caught in the LEZ, which is designed to improve air quality.
Initial £60 penalties will approximately double for each repeat offence within 90 days, up to £420 for cars and vans, and £900 for lorries.
Glasgow’s LEZ will see 12 cameras rotated between every entry point, with enforcement starting in 2023.
Mike Birch, of Living Streets Edinburgh, said "Given that the LEZ is intended to operate 24/7, we are concerned that this approach will affect the levels of compliance required for the LEZ to achieve the intended reduction in atmospheric pollution and health benefits.
"We are further concerned this approach will encourage the drivers of non-compliant vehicles to use the non-arterial routes to avoid detection, thus increasing traffic further in the many residential streets bounding the proposed LEZ.
"We believe that to achieve the required compliance for the success of the LEZ, it is critical that enforcement is rigorously applied.
"There are already too many council transport-related initiatives, such as 20mph speed limits, parking and loading restrictions, and prohibition of idling stationary vehicles, that have foundered due to lack of effective enforcement."
However, Edinburgh City Council transport convener Lesley Macinnes said: “Contrary to what’s being alleged, our LEZ proposals have been robustly developed to make sure drivers in the most polluting vehicles would be discouraged from entering the LEZ.
“ANPR cameras linked to a national licensing database will monitor vehicles driving into the zone and detect any which don’t comply with minimum emission standards.
"Another deterrent is the mobile unit, which will patrol the whole zone and detect non-compliant vehicles, while the escalating penalty charge structure which increases for repeat offences in line with national regulations will be a further disincentive to enter the LEZ.
“I also take exception to the claims made about other transport initiatives in the city ‘foundering’.
"Our pioneering 20mph rollout has made Edinburgh’s roads safer, with a statistically-significant drop in speeds.
"Parking enforcement is managed throughout the city using innovative beat patterns and targeted deployment in known hot-spots, our bus lanes are kept clear and safe due to camera enforcement.
"Drivers of idling vehicles are dealt with whenever possible.”
A Glasgow City Council spokesperson said: “Numbers are subject to change, but it is proposed the camera locations will be fixed and cover all entry roads into the LEZ.
"Our current proposals are for 12 cameras to service these locations, which will be rotated randomly around the available camera locations.”