Labour says it's outrageous the government is considering letting in thousands of tonnes of palm kernel that could be contaminated.

Some 23,000 tonnes of the product is on board cargo ship MV Molat, which the Ministry for Primary Industries stopped at the border amid fears it could endanger our agricultural sector.

It has been anchored several kilometres off the Tauranga Port since early September.

Labour's Biosecurity spokesman Damien O'Connor said the Ministry needs to send the boat on its way.

"It's an outrageous situation that the government and MPI have taken four weeks to hopefully say no to what is a high-risk shipment of palm kernel."

The shipment has come from an unregistered supplier in Malaysia and the ministry is working with the importer, which it's not naming.