Hong Kong's government said late on Saturday there were no initial systemic issues found in BioNTech's vaccine packaging.
Hong Kong and Macau authorities halted the German-made drug's use earlier in the week, after discovering several broken vials.
In Saturday's statement, the city's government said BioNTech's defective packaging could still be due to "environmental conditions during the long-haul transport process."
Though it added the situation was not related to the logistical management of the vaccine.
Hong Kong has faced a sluggish take-up of vaccines because of dwindling confidence in China's Sinovac and fears of adverse reactions, while the suspension of BioNTech's vaccine distributed by China's Fosun Pharma triggered confusion in inoculation centres across the city.
Both BioNTech and Fosun consider their vaccines to have no safety risks, and people who have already received them "do not need to worry."
The government said it plans to complete their investigation within a week and resume supplying the vaccines to the public.