A man has been taken to hospital in a serious condition following an incident yesterday evening in Invercargill's CBD.

Hato Hone St John received a call at 7.16pm and responded with two ambulances.

The patient was treated at the scene before being transported to Southland Hospital, a St John spokeperson said.

Invercargill Central spokeperson Rebecca Sheppard said she had been advised by Amalgamated Builders Ltd that a subcontractor working on the CBD site had been injured and was being treated in hospital.

"All relevant parties have been notified and an incident investigation is underway," she said.

A Worksafe spokesperson confirmed they had been notified and were making initial inquiries.

The Southland App understands the worker may have fallen from a height. Following the incident, a site meeting was called but no site shut-down has occurred.