Some vehicle test centre staff have been on strike since last month

The Limavady-based company, Sandy Arthur Training, teaches HGV drivers, but has not been able to get driving tests for them during the industrial action.

Members of the civil service union Nipsa began strike action last month at nine vehicle testing centres in Northern Ireland.

Sandy Arthur, who runs the private training company, said its customers were not able to get driving tests during the strike.

"We employ somewhere in the region of 20 staff, about 10 of whom are involved in heavy goods vehicle training," he said.

"At the moment, it looks like we are going to have to lay off some of these staff."

Unofficial walkout

Public services were further disrupted on Thursday after Rate Collection Agency staff staged an unofficial walkout.

The strike action, by up to 60 members of Nipsa, seriously affected the Agency's Belfast and Craigavon offices.

Union officials say it was a show of support for four members of staff who were suspended without pay.

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.