The laboratory will allow Pacific nations to develop controls for emerging biosecurity threats, including pests and diseases.
The SPC deputy director-general, Audrey Aumua, said invasive species cost billions of dollars each year to control.
She said the new laboratory would provide biological solutions to aid Pacific farmers and lead to safer food production.
The plant health laboratory enabled scientists to study pests and diseases requiring a high level of biosecurity containment, such as insects, fungi, viruses, and bacteria.
The launch coincided with the United Nations' declaration of 2020 as the International Year of Plant Health, which sought to help reduce poverty and hunger, protect the environment, and boost economic development.