Three men caught smuggling nearly 40kg of methamphetamine worth $24 million from Mexico, in what was the South Island's biggest-ever P bust, have today each been jailed for at least 12 years.

Jonathan Seal, 27, Michael Harrison Cooper, 33, and Auckland freight worker Simote Vea, 38, were arrested after a joint police and customs Operation Grandeur investigation.

Drugs hidden in a shipment of safety lights landed at Christchurch International Airport from Mexico on November 1, 2017.

Officers found 20 separate boxes, each with 1.1-1.2kg of 80 per cent pure methamphetamine, totalling 39.7kg.

Search warrants were executed at a number of addresses in Christchurch and in Auckland after a two-week joint police and Customs operation.

Today at the High Court in Christchurch, the trio received hefty jail sentences for their roles in the drug smuggling – with father-of-four Vea sentenced to 15 years and seven months imprisonment with a minimum non-parole period of seven-and-a-half years, and Seal and Cooper each jailed for 12 years and four months, with no minimum non-parole periods.