A ship carrying 50,000 New Zealand sheep and 3000 cattle on a 11,000km trip is only required to have one veterinarian on board, the Ministry of Primary Industries says.
The massive shipment of live sheep to Mexico has prompted concerns about animal welfare and led Oppositions MPs to question whether New Zealand's policy of not exporting livestock for slaughter was being breached.
A Ministry of Primary Industries (MPI) spokesman said today that there were a range of checks and balances for live animal exports to ensure animal welfare standards were maintained.
"With any approvals of livestock for export, the welfare of the animals is the highest consideration," the spokesman said.
The ministry said the animals are being exported for breeding in Mexico, where there was huge demand for sheep and cattle following a recent drought.
Approval was only given once the ministry's director-general was satisfied that all conditions, including animal welfare requirements, had been met.
Exporters must sign a statutory declaration that the animals were intended for breeding.
Approval for any future shipments would depend on an exporter's compliance record.
The spokesman said the sheep had to be accompanied by "suitable experienced stockmen" and "at least one veterinarian".
If there were unusual levels of deaths or sickness among the animals, it had to be reported to MPI, and a report on their conditions had to be produced within 10 days of the shipment.
Labour Party trade spokesman David Parker said New Zealanders expected the Government to openly show how it would guarantee and monitor the health of the sheep with just a single vet on board.
He said there was too much secrecy around the shipment, given past controversies and problems with live exports.
"New Zealand's international reputation for humane treatment of animals is very important to the premium price New Zealand farmers get for chilled lamb exports," Mr Parker said.
The Labour-led Government banned live exports for slaughter in 2003.
Green Party co-leader James Shaw said today that if the Government supported the ban, it would have enforceable animal welfare regulations at the exporter's destination.
He said: "The Government knows the public will be outraged if the ban on exports for slaughter was scarped, so they are getting around this by allowing sheep to be shipped off for 'breeding purposes', even though there is no way of ensuring that the sheep are not slaughtered upon arrival."