Seven people have been arrested for trying to import more than 100 kilograms of methamphetamine into the country.

The shipment, which arrived in August from China, was disguised as concrete inside the base of outdoor umbrella stands.

It's been linked to a company believed to have been set up solely to smuggle drugs.

Customs said this type of concealment is difficult to detect and the discovery came down to good investigative work.

It says the syndicate used multiple people for different roles, in a bid to avoid detection by law enforcement.

The drug haul has a street value of between $100 million and $120 million dollars.

Detective Superintendent Greg Williams said a joint effort by police and customs led to the discovery.

He said the seizure has prevented a huge social harm from happening.