Welfare concerns surround New Zealand's largest ever live sheep export consignment as the animals are loaded onto a ship bound for Mexico.
Fifty thousand sheep will be loaded aboard a ship in the Port of Timaru overnight before its departure to Central America tomorrow morning.
The sheep will be part of a breeding programme in Mexico.
A week-long ONE News investigation into the controversial shipment began after a local farmer raised concerns about the animals' welfare.
Animal Welfare organisation, Safe, believes that many of the sheep will die on the more than 11,000km voyage.
Safe Executive Director Hans Kriek said: "These animals are going to suffer badly. Some of these animals will refuse to eat and will die of starvation."
Prime Minister John Key said the sheep were to aid Mexico's agriculture industry which was suffering from a "huge drought".
"A lot of their breeding stock were wiped out and so they've asked us to send these sheep."
He dismissed any rumours of a secret shipment by saying: "We can't keep a boat that size secret, it's huge ... it's a large number but it's not the first time we've exported large numbers."
Sheep exports are allowed if the animals are intended to be used for breeding, despite a ban on sheep exports for slaughter.
Mr Kriek said he wanted a ban on breeding exports too.
"This is really an escalation of an export which we already have real concerns about and this is just way over the top.
"It is cruel to the animals and it will do no good for New Zealand's reputation," he said.