A Chinese couple who arrived in New Zealand for the birth of their grandchild were deported after they were caught trying to smuggle edible bird nests into the country, New Zealand border officials said Thursday.

The couple, who arrived at Auckland on a flight from Shanghai Tuesday, had denied carrying any items that could have been a biosecurity risk, according to the Ministry for Primary Industries (MPI).

But MPI quarantine officers at Auckland Airport noticed possible organic material in the couple's luggage during x-ray screening.

The nests were found in "a vacuum-packed blanket" and the couple, who had traveled to New Zealand for the birth of their grandchild, were denied entry and ordered to return home on Tuesday night.

"We believed the action was a deliberate smuggling attempt of an item that could have carried avian diseases with the potential to wipe out New Zealand's native and commercial bird populations," MPI Northern Border Clearance Manager Craig Hughes said in a statement.

Bird nest soup is widely believed by the Chinese people to be a precious and nutritious food, which is especially helpful for the recovery of new moms.