The scheme will expire on June 30, but nearly 100,000 people who are eligible haven’t claimed their discount.
Motorists are eligible for free 12-month vehicle registration if they have spent $1462 or more.
The cashback scheme will replace the reduced registration scheme going forward.
Brian Moore from Service NSW urged drivers to renew their registration now as it can be done up to three months in advance.
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The areas where the most drivers have saved on their rego are Kellyville, Rouse Hill, Baulkham Hills, Westmead and Liverpool, as they are the ones doing the most travelling on toll roads.
These relief measures were introduced by the former Coalition government.
Premier Chris Minns made an election promise to increase assistance by implementing a $60-a-week cap on tolls but it is yet to come into effect.