Drivers in Northern Ireland have just two weeks to tax their vehicles at offices here before services are transferred to Wales.
Under new arrangements introduced by the Department for Transport in London, after Thursday, July 17 the Driver and Vehicle Agency (DVA) in Northern Ireland will no longer tax and register vehicles.
This will instead be done by the Driver and Vehicle Licensing Agency (DVLA) in Swansea.
Services will be taken up by the Welsh workers from Monday, July 21.
As a result, more than 300 DVA jobs are being lost, mainly in Coleraine.
At close of business on Thursday, July 17, DVA offices in Northern Ireland will cease to tax and register vehicles over the counter and they will be unable to process any postal applications which are posted after July 11.
Simple car tax renewals will be possible at some post offices. However, after July 17, drivers will be encouraged to tax their vehicles online. Post Offices will offer additional services.
The DVA has issued advice to Northern Ireland motorists who need to tax their vehicles during the transition period.
DVA chief executive Paul Duffy said it was aimed that the switch should run as smoothly as possible.
"It is important that anyone seeking to tax their vehicle knows exactly how the new system will work," he said.
"The changeover to a new system should be as smooth as possible for local motorists.
"I have thus advised the DVLA officials in Swansea that they need to communicate with people taxing their cars here as clearly and timely as possible."
Mr Duffy praised DVA staff in Northern Ireland as having provided a "first class service to motorists here".
"They have set a very high standard for the DVLA in Swansea to follow when it takes over full responsibility for all vehicle licensing services from July 21," he said.
The DVA's other functions: driver licensing, driver and vehicle testing, bus and taxi licensing and roadside compliance checks are not affected by the transfer of vehicle licensing to Swansea.
The identity checking service for first time applicants for provisional driving licences currently provided at motor tax offices will be available from Monday July 21 at Driver Licensing HQ, County Hall, Coleraine, and at the following test centres: Armagh, Ballymena, Belfast, Downpatrick, Enniskillen, Derry and Omagh.
Further information is available at nidirect.
A leaflet explaining the new system will be issued with all car tax reminders from July 5.
Leaflets explaining the changes are available at DVA offices.