Acting Detective Inspector Karl Thornton said the police seized the pills after they were informed of the test results.
They followed that up by searching a Hillcrest property, where they found chemicals, equipment and explosives, he said.
Defence Force personnel removed the explosives for "analysis and destruction".
Neighbours of the property were evacuated and a 200m cordon was established," Mr Thorton said.
"As part of these procedures a nearby school was contacted and advised of the situation and students were requested to leave school via the front entrance, not via the rear."
"In addition to the explosives, chemicals and equipment were removed and sent for analysis to determine their composition and legal status."
A police guard was in place overnight at the property ahead of a search set to resume this morning.
The 26-year-old man was arrested and charged with importing Class B and C controlled drugs and is expected to appear in Hamilton District Court today.