June 24 (Reuters) - Cathay Pacific Airways Ltd (0293.HK) said on Thursday that all Hong Kong-based pilots and flight attendants would need to be vaccinated against COVID-19 by Aug. 31 or risk losing their jobs, in one of the airline industry"s toughest policies. Cathay said it had struggled with staff rostering due to Hong Kong"s strict quarantine rules on return that have been loosened for crew that have been vaccinated. There are also requirements that only fully vaccinated crews can operate to certain high-risk destinations and on quarantine-free "bubble" flights. Hong Kong has a surplus of unused vaccines and some of the shots are about to expire, city authorities have said. read more Cathay said 90% of pilots and more than 65% of cabin crew had been vaccinated already, or had appointments for vaccinations, following a previous warning that vaccination was highly likely to become compulsory. "We understand there will be some who cannot take a vaccine and we will look into accommodating them on a short-term basis where we can," the airline said in a statement. "However, we will review the future employment of those who are unable to become vaccinated and assess whether they can continue to be employed as aircrew with Cathay Pacific." Cathay"s new policy was first reported by the South China Morning Post and comes amid varying industry approaches to crew vaccinations. United Airlines Holdings Inc (UAL.O) said on Tuesday it would mandate full vaccination for crew members flying to countries with high COVID-19 cases at the beginning of August, while Delta Air Lines Inc (DAL.N) last month said all new hires would have to be vaccinated. read more Australia"s Qantas Airways Ltd (QAN.AX) has said it will require all passengers and crew to be vaccinated when the country"s borders reopen to widespread international travel. Emirates has provided employees with free vaccines since January, and later told staff they had to get vaccinated or pay for regular tests to prove they are not infected.