Police have arrested two men and seized firearms, drugs and thousands of dollars in cash after an anonymous tip to Crimestoppers led them to a clandestine P lab in South Auckland.

Counties Manukau police said the tip meant they had halted a significant drug operation in a Clover Park house.

During the raid, police seized nearly $31,600 in cash, 304 healthy cannabis plants that were being grown hydroponically, 90 grams of meth, two firearms and two large hunting knives.

The two men were charged with drug offences.