As a precautionary measure, six staff members showered on-site and changed their clothing to decontaminate, he said.
He said the team's main priority was keeping staff safe.
The building was not evacuated and had remained open to the public, he said.
This was not the first time this had happened in the building and he said it was great how smoothly the staff had handled the situation.
Everything was "back to normal" now, he said. The incident had been handed over to police.
Tauranga Fire Station officer Nigel Liddicoat said it was unknown what was in the package and it would be sent down to Wellington for testing.
He said the staff had followed procedure by self-isolating in the mailroom before the parcel was stabilised in a chemical drum and taken away.