The facility will also have the capacity to detect priority pathogens such as influenza and dengue.
The lab was supported by the World Health Organisation (WHO) with funding from the Indian Government.
Matangi Tonga reports the Minister of Health, Dr Saia Piukala, saying at the launch Covid-19 is not yet over and testing in Tonga remains a priority.
"During the pandemic we have strengthened our laboratory capacities to be able to test Covid-19 quickly and accurately, but also to be able to test for the many other diseases we will face in future. This support from WHO, UN and the Government of India is a welcome development in order for us to boost our testing capacity here in Tonga."
The new laboratory was pre-built in New Zealand using shipping containers.
Testing machines, laboratory supplies, staffing, operational support, and quality assurance programme and training were also provided by the WHO.
Dr Yutaro Setoya, WHO Country Liaison Officer in Tonga, said the new container laboratory will help not only in the ongoing Covid-19 response, but will also be critical in the detection and surveillance of potential disease outbreaks in the future.