Co-ordinated police raids across Northland have uncovered LSD, methamphetamine, firearms and four commercial indoor cannabis operations.

Ten people were arrested during the weekend operation as police searched properties in Kaikohe, Kerikeri, Towai, and Waipapa.

Detective Sergeant Rhys Johnston, in charge of Mid North CIB, told the Northern Advocate the raids were the result of follow-up investigations into the death of a 16-month-old Kerikeri baby Riley Osborne.

Kyle Skerten, 21, beneficiary, was charged with murdering Riley who died in December last year after being admitted to hospital with serious head injuries.

Skerten also faces charges of possession of methamphetamine, two of possession for supply and three of supplying equipment for producing methamphetamine. He is due back in court this week.

Those arrested during the latest raids appeared in Kaikohe District Court yesterday on drug charges including supply of methamphetamine, selling LSD, and possession of cannabis for supply.

Some of the accused faced cultivation of cannabis charges and others appeared on firearms-related offences after two pump-action shotguns and a variety of rifles were seized. More than 1.5kg of cannabis was found.

The weekend operation comes only a few months after record numbers of people were arrested and cannabis plants destroyed in the annual blitz on Northland's multi-million dollar drug trade.

Some 67,508 cannabis plants were ripped out or doused with blue herbicide and 245 people were arrested.

Northland's top policeman, Superintendent Mike Rusbatch, said 40 per cent of the country's cannabis crop was grown in Northland.