A massive drug bust in Hawke's Bay has led to 20 arrests.

A five-month operation to stop the ongoing supply of methamphetamine and cannabis has wrapped up, after 11 search warrants were executed throughout Napier and Hastings yesterday and today.

20 people - men and women aged from 20 to 50 - have been arrested and charged with multiple drug offences and participating in an organised criminal group.

Detective Inspector Mike Foster said Police seized more than $35,000 in cash - much of which was buried - methamphetamine, LSD, large amounts of cannabis and a 12 gauge rifle.

The Armed Offenders Squad was used at one address, where the firearm was found.