WELLINGTON, July 7 (Reuters) - New Zealand"s closed borders have helped keep COVID-19 out of the Pacific nation, but a critical shortage of migrant labour is now fuelling protests among businesses and workers struggling with a staffing crisis. About 2,000 eateries stopped service and turned off lights across on Tuesday and are planning other stop work events as part of a two-month campaign to draw the government"s attention to the severe shortages in skilled labour. The labour crunch comes after New Zealand sealed its border in March last year in response to the raging coronavirus pandemic. The measures helped contain COVID-19 locally, and Prime Minister Jacinda Ardern has vowed to maintain an elimination strategy that"s been lauded globally. But although the COVID-free economy has bounced back faster than expected, its vaccination rate is much lower than developed peers and immigration has hit historic lows, leading to acute labour shortages in a country that relies on low-skilled migrant workers. "Before COVID-19 hit and closed our borders upwards of 25% of our workforce were international work visa holders," Restaurant Association on New Zealand, an industry body organising the protests, said in a statement. "Losing them is enough to make a difference so big that it can affect a business in catastrophic ways," the association said. Some restaurants in Auckland and other major cities temporarily shut due to understaffing or just to give their burnt out staff a break, media reports have said. Adding to business frustrations is the government"s reset on immigration announced in May, which would further cut the number of low-skilled migrants when borders eventually re-open, and look to attract more highly skilled migrants and rich investors. "If the government don"t reverse this policy, more restaurants will shut down and that"s sad, and potentially new and great restaurants won"t be able to open because the innovators out there will find it too hard to start recruiting,” National President of Restaurant Association of New Zealand Mike Egan told local media 1NEWS. Hiring constraints are increasing across several industries, a business survey noted this week, with firms reporting they were finding it more difficult before to hire skilled labour. read more Essential services workers are also upset. About 30,000 nurses are set to walk off their jobs later this year in a series of strikes for better pay and working conditions as they complained of burnout. "We are facing a national health crisis in terms of safe staffing, recruitment and retention; and the working conditions our members face can no longer be endured and that"s why our issues matter," the New Zealand Nurses Organisation lead advocate David Wait said in a statement.