The remaining seals at Napier's Marineland are still undergoing pre-quarantine checks.
The eight seals began the quarantine process in late January. There have been delays in reaching full compliance and, as a result, the seals are yet to enter the required 120-day pre-export quarantine process.
"While the delay is disappointing the main thing is the seals remain in good hands and are being well looked after by our team," tourism services manager Neil Fergus said.
"This is an unusual case with procedure, protocols and infrastructure having to be adapted to suit these circumstances which has taken longer than we anticipated."
The seals will be rehomed at zoos in Australia.