The Capital District Health Authority says the strike led to 91 surgeries being postponed along with 300 outpatient appointments being put off at clinics that were supposed to see 1,665 patients on Thursday.
By the end of the day, Capital Health says 227 out of a total of 740 beds will be closed.
The strike is expected to be short as the government pushes through essential services legislation that's likely to become law Friday.
Capital Health CEO Chris Power said the strike's impact is significant for patients.
"The inconvenience to us as a system is nothing compared to what it is to our patients," she said. "And for people who have waited months and months for surgery and procedures to only have it cancelled and now have to get in the queue again, no matter where it is, the disruption to families, the emotional stress that people are undergoing is tremendous."
Striking nurses say the strike is about patient safety as the Nova Scotia Government and General Employees Union tries to get a collective agreement that includes mandated nurse-to-patient ratios.
"We want to get the word across about safety for all because this affects everybody," said Jennifer Derengoski, 31, a neurosurgery nurse.
Paolo Amati, 50, an operating room nurse, said more nurses are needed to ensure patient safety.
"It's about safety," he added. "And what's important is that hopefully this government will understand that you can't go on with something you don't have. ... It's a national worry."
The strike affects services at a handful of hospitals and health centres in the city, but its impact has already been felt across the Maritimes.
The hospitals provide medical treatment to people in the three Maritime provinces and some patients have already been transferred to other health districts in the region.
Union president Joan Jessome said the union will end its legal strike once the essential services legislation passes.
Capital Health said 234 surgeries have been postponed since Monday, but Jessome said operations are cancelled even when hospitals are operating normally.
"The amount of surgeries that are cancelled on a weekly basis at Capital Health goes untold, but because this is such a public fight, they're (the public) seeing these numbers over the past couple of days," she said.
A few hundred of the 2,400 nurses represented by the union staged a wildcat walkout Tuesday that forced the cancellation of dozens of surgeries as they protested against the bill introduced by the province's Liberal government.
The union's demand for higher staffing levels has been rejected by Capital Health, which says mandated nurse-to-patient ratios won't work because they are too inflexible and there is no evidence they improve safety.
The union and the health authority have agreed to maintain full staffing levels for emergency rooms and units offering dialysis, cancer care and intensive care. Jessome said up to 60 per cent of the union's members in Local 97 will work during the strike.
Premier Stephen McNeil has said the law would not take away a union's right to strike because that option remains open once essential staffing levels have been negotiated or determined by the Nova Scotia Labour Board. The nurses' union says such deals can take up to six months to reach, effectively undermining the leverage of a strike.
The law would apply to as many as 40,000 workers including nurses, paramedics, ambulance dispatchers, hospital employees and people who work in homes for seniors, youth and people with disabilities.
The nurses primarily work at four places in the Halifax area: the QEII Health Sciences Centre, Nova Scotia Hospital, East Coast Forensic Hospital and Public Health Services. The region's largest children's hospital, the IWK Health Centre in Halifax, is staffed by nurses from another union.