Approximately 7300 live cows are being exported from Napier to China this week.
The cattle are being exported for breeding to develop the dairy and livestock industries in the receiving country, an MPI spokesperson said.
They will be transported on livestock carrier ship Dareen.
The Yangtze Harmony also collected a consignment of cows from Port Taranaki this week.
Animal rights activist group Safe has raised concerns about the exports after an investigation by Australian Federal agencies into the inhumane slaughter of Australian cattle in Indonesia.
Safe campaigns manager Marianne Macdonald questioned what assurances Agriculture Minister Damien O'Connor can give that the same thing wasn't happening to New Zealand-sourced animals going to China.
"Tens of thousands of cows have been exported from New Zealand to destination countries with no laws protecting the way they are treated once there.
"We're particularly concerned over the methods that will be used when they are slaughtered. They will likely still be conscious when their throats are cut."
She said there was no way to stop the suffering of animals once they arrived in their destination countries.
An MPI spokesperson said animals are not permitted to be exported for slaughter.
O'Connor said that when animals leave New Zealand, conditions "considered world class by veterinarians are set".
MPI said one person experienced in handling animals must be on board for every 1500 animals.
Animals are given food, water and space, and and medicine and equipment is on hand for sick animals.
When animals arrive MPI has no jurisdiction in foreign countries but the importer has to provide a report on how the animals travelled within 20 working days of the voyage ends, and 30 days after the animals arrive a report on the condition of the animals is also required.
"The importers have made a significant commercial investment in these cows, so it is in their interests to ensure they are well cared for and maintained in excellent condition," O'Connor said.
O'Connor said a number of cattle in recent shipments would have likely gone to slaughter in New Zealand.
"The ability for farmers to export at this time relieves pressure from a shortage of feed as a result of a major drought, which is still affecting a lot of farmers around New Zealand."
O'Connor said that decisions from a review into live exports have been delayed because the Government needs to prioritise the response to and recovery from Covid-19.
"Until the outcomes of the review are determined, MPI will continue to consider applications for the export of cattle, deer, goats and sheep (livestock) under the current law," he said.
But Macdonald said it should be banned.
"The Minister will not be releasing his review into live exports until after the election. Given the growing body of international evidence of the cruelty associated with live export, it's clear that the trade must be banned," Macdonald said.