Motorists will be able to get their car tested any time before their normal NCT date under new measures to be announced today.
Where the vehicle passes the test, it will receive a two-year (or one-year for vehicles older than 10 years) cert from the date it passes the test.
Up to this, they could test a maximum of 90 days prior to the due date.
Owners will also see their car mileage recorded on the NCT cert in a bid to stop "clocking", or changing the genuine odometer reading of the car in order to make the car seem like it has driven a shorter distance than it actually has.
Up to three previous readings can be printed on the cert.
In order for a vehicle to be considered as presented voluntarily early, it must currently have an in-date, valid NCT test certificate or be younger than four years and 90 days.
A statement on the NCT website said: "This change is being introduced as members of the retail trade have lobbied for it as they see an advantage in being able to sell a vehicle with a full two-year (or one-year) certificate."