Quick thinking from border control officers lead to the seizure of five-kilos of ecstasy at Christchurch Airport.

Two Russian nationals will each spend more than five years behind bars, after pleading guilty to trying to import the drugs, which have a street worth of around $2 million.

NZ Customs manager of central and southern ports, Joe Cannon, says the drugs were well hidden, having been sewed into the lining of a suitcase, but customs officials knew something wasn't quite right.

"We weighed the item when it was empty, didn't quite stack up. We then x-rayed the item and after that we drilled into it because we were very concerned at that point in time."

Canon says last year also saw the largest seizure of methamphetamine for the South Island after $50 million worth was found concealed in an airfreight consignment.

"I think some people may have thought they could get away with it, what we have done, last year, is proven that is wrong."