A strike by the majority of public sector workers in Northern Ireland shut schools, halted transport services and left icy roads ungritted on Thursday, with people warned to only travel or seek medical help in an emergency.

The 24-hour strike, which trade unions said was the largest in a generation, was called after workers failed to receive pay increases despite multi-decade high inflation, following the collapse of the region's power-sharing government in early 2022.

The walkout by some 170,000 nurses, teachers, train drivers and other workers will add pressure on the Democratic Unionist Party (DUP) to end its two-year protest over Britain's attempts to settle post-Brexit trade rules for the region.

Public pay has risen in the rest of the United Kingdom and the British government pledged last month to provide the funds for pay rises if power-sharing resumes. Local politicians and unions say London should push through the hikes regardless.

The strike began amid a yellow weather warning for ice, prompting warnings that road journeys should be limited to essential travel only due to the conditions and limited gritting. Road service staff are among those set to strike for a week.

The health service asked the public to "take all sensible steps" to reduce their chances of requiring care and assume any appointments due on Thursday were cancelled.

Northern Ireland's Chief Nursing Officer said the disruption to services "could be on a scale not previously witnessed."

The DUP says it will only return to government once it wins further concessions on the trade rules London agreed with the EU upon leaving the bloc. Many unionists feel any barrier to trade undermines their place in the United Kingdom.

Irish nationalists and pro-British unionist politicians are obliged to share power under the terms of the 1998 Good Friday peace accord that ended three decades of sectarian violence in Northern Ireland. (Reporting by Amanda Ferguson, writing by Padraic Halpin, editing by Christina Fincher)