Seven test centres have been closed since Monday
The government has been urged to bring the MoT system in Northern Ireland into line with the rest of the UK, where tests on private cars are carried out by
The call came from the Federation of Small Businesses (FSB) as the indefinite strike started by public service union NIPSA members on Monday caused mounting problems.
The Driver and Vehicle Testing Agency warned of disruption to appointments at seven centres, namely Armagh, Belfast, Craigavon, Lisburn, Mallusk, Newry and Newtownards.
Some 5,000 MoTs were expected to be cancelled this week and the situation could get worse next week when two more centres join the strike.
The government has made clear that despite the strike it is not relaxing its requirement for a current MoT certificate when a car over four years old is re-taxed.
Wilfred Mitchell of the FSB called for a government re-think on testing.
He said: "It is surely time for the government to consider changing the current system in Northern Ireland to that used in other
parts of the UK, where private vehicles can be tested by local licensed garages
as opposed to government-run centres."
He said if the government moved to that system it would "provide significant
business opportunities to garages in Northern Ireland" and would ensure the
negative effect of industrial action was minimised.
He said the FSB accepted the UK model still had government-run MoT centres for
commercial and passenger vehicles.
However, he said it would still provide a competitive service, choice to the general public and "create opportunities for garage owners".
Nipsa has been involved in strike action since December over what they said was the government's refusal to give civil service staff any cost of living increases in rates of pay since April last year.
The government has imposed a pay package which will add 3.67% to the wage bill of the Northern Ireland Civil Service.
However, union officials say that was part of a pre-agreed increment and takes no account of the rise in the cost of living.