Port Marlborough says EcoWorld is acting illegally by refusing to leave the building which houses its aquarium.
EcoWorld has made headlines in previous weeks for refusing to leave its Picton site, claiming Port Marlborough is kicking them out without warning and refusing to act reasonably.
On Thursday, EcoWorld's lease ended, and executive director John Reuhman staged a sit-it, refusing to vacate the premises.
He's also filed with the High Court, saying he has a lease that the Port is denying.
But a spokesperson for the Port says this is false.
"The lease was entered into in January 2011 and was for a 10 year period, with no right of renewal. The terms of the lease also oblige Ecoworld to remove any improvements to the land and reinstate that land at its expense," they told Newshub.
"The lease is simply ending on the agreed terms. Mr Reuhman is alleging that Port Marlborough agreed to renew the lease or to a new one. That is not the case."
The spokesperson says Reuhman sought to alter his lease in ways which were "unacceptable and fundamentally different to his existing lease" - and the Port could not possibly agree.
Although it did not extend the lease, the Port did offer money to help rehome the animals - which Reuhman said would need to be "slaughtered", waiving EcoWorld's end of lease obligations and extending the lease rent-free.
"These offers have thus far been rejected and misrepresented by EcoWorld," the spokesperson said.
Port Marlborough chief executive Rhys Welbourne says he is consulting with the community to look at options for 'transforming" the site to deliver better "cultural, environmental and economic benefits".
"We have acted in accordance with our values when negotiating with EcoWorld and will
continue to do so."
