"Our priority is addressing the affected area rather than establishing the history of the building," Mr Francis told the Bay of Plenty Times.
"We have employed specialists to come in and examine the site.
"It is still early stages of the investigation and as we know more we will advise the public."
Mr Francis said Worksafe NZ, the Bay of Plenty Regional Council and Tauranga City Council were informed and there was no immediate health risk to staff or the community.
Specialist contractors were expected at the site this morning to remove the asbestos safely.
"The site has been secured in line with regulations and we are currently working ... to determine the best disposal measures going ahead," Mr Francis said.
"We hope to have a disposal method confirmed later this month."
Mr Francis said the discovery and removal had not held up progress on the Maungatapu underpass.
The underpass is being built on State Highway 29A underneath the Maungatapu roundabout and will connect to Welcome Bay Rd.
Along with the underpass, the project includes new cycle links and a cycle and pedestrian bridge above SH29A.
The underpass is expected to separate state highway and local traffic, reducing congestion at peak times and making travel safer for pedestrians and cyclists.
The area where the asbestos site was found lies near Hammond St, which has been closed to traffic while construction of the underpass continues.
Residential traffic is using a new access way on SH29A until the Hammond St access onto Welcome Bay Rd returns when the project is complete.
