The National Roads Authority has assured M50 drivers that those who have registered for electronic tags will receive them before barrier-free tolling is introduced this weekend.
Most drivers who have signed up for eFlow have not yet received their pass.
From midnight on Friday motorists will no longer be able to pay cash at the M50 toll-bridge in west Dublin.
The NRA estimates that about 250,000 drivers have already registered their number-plates or bought electronic tags ahead of the switchover.
Tag-registered car drivers will be charged €2 to use the toll-bridge but it will cost non-registered drivers €3.
The NRA today assured drivers that they will have their tags by Friday night, and guaranteed those who do not that they will not be subjected to any fines or penalties.
Non-registered drivers will be able to pay their toll either before or after using the motorway in most newsagents, convenience stores and some petrol stations. They can also pay online at eflow.ie
While it is legal for retailers to add a surcharge to the toll amount at the Payzone point of sale, the NRA has said this will not happen.