Detective Sergeant Derek Shaw said officers searched a Lake Hāwea property where they found the class-A drug, cannabis and three guns.
"With this operation, police have caused significant disruption to a national supply chain that has been responsible for immeasurable harm," Shaw said.
"Methamphetamine is a horrendous drug which can have a devastating impact, especially on our youth and vulnerable people. It affects not only the person using it, but their families, friends and their wider community."
Police asked anyone with information about the supply of illicit drugs to report it on 105 or anonymously via Crimestoppers on 0800 555 111.