Marshall, who founded Eftpos, said 15 other parties were involved in the zone-change process at the same time.
Simultaneously, the company was in negotiations with Silverlight Studios to buy the land.
At the present point Silverlight has entered into a conditional contract with Corbridge Estate, but the sale has not been completed.
Marshall said its legal team had been pushing for the report from the council — the council stated it would not be released until March 18.
"We went 'fine', that's the day it's going to happen.
"And then a particular planner at the council, to a totally un-bona fide person, who happened to be doing some work for the studios, rang up and said, 'Can you give us a heads-up on what's happening with the Corbridge decision?"'
The planner subsequently released that decision to the third party, as well as all 15 others.
Marshall said the error had resulted in an "unquantifiable" loss.
In a statement, council planning and development general manager Tony Avery said the council issued an apology to "a party who was potentially affected by the release". The departure from the usual process was a "regrettable error" that would not be repeated.
Marshall understood the planner responsible, and other staff, had subsequently resigned.
"As far as we're concerned, we're pursuing all our avenues with the council right now, basically saying 'You've got to deal with this'.
"Commercially, it was embarrassing for us because we're in all sorts of negotiations.
"For the council to start releasing information, unauthorised, to unauthorised parties, is that how they operate?"
Marshall said he had sought further information from the council about how the error occurred and was waiting for that to be provided before the company considered its next step.
"We're taking them to task — we're not giving up on this."