Benefit payments to top up the wages of low-paid workers will be stopped if they go on strike, the Government has announced.
Employees eligible for working tax credits because they earn under £13,000 will no longer receive extra cash if their salary nose-dives because they take industrial action.
Bosses will be given a code to alert the authorities if any drop in wages has been caused as a result of a walkout when all welfare payments are brought under the new Universal Credit system next year.
Work and Pensions Secretary Iain Duncan Smith said the current rules were out of date and unfair.
"It is totally wrong that the current benefit system compensates workers and tops up their income when they go on strike," he said. "This is unfair to taxpayers and creates perverse incentives.