New York City Mayor Bill de Blasio is set to fulfill a campaign promise by announcing a significant expansion of a law that requires employers to give workers paid sick days.

Two sources familiar with the matter who were not authorized to speak about the law until de Blasio announces it on Friday said it will provide sick days for an additional 300,000 New Yorkers.

Under the current law, which was enacted in June, employees of businesses with 20 or more workers would get up to five paid sick days a year beginning in April 2014.

The new legislation, which has long been a dream of liberal politicians and activists, is expected to require that businesses with five or more employees provide the five sick days.

De Blasio, a Democrat, made the expansion a major plank of his mayoral campaign. His rival, City Council Speaker Christine Quinn, had initially opposed the paid sick legislation last year, which later hurt her in the very liberal Democratic primary.

Advocates of the law argued that workers shouldn’t have to choose between their physical and financial health and customers and colleagues shouldn’t have to be exposed to employees who come to work sick.

But critics said that the government should leave sick day arrangements to workers and bosses and that the requirement will burden small businesses.

De Blasio is to announce the deal at a Brooklyn restaurant with newly-elected City Council Speaker Melissa Mark-Viverito, a close ally whom he helped to install as speaker, sources said.

(AP)