His company, which makes 95 per cent of its income from scripts, sought and got an interim injunction from the High Court on Friday to prevent the second pharmacy from operating at the building while the argument is decided.
Gaur says in 2012, during a restructure at the centre, he was told by the medical practice's founder, Dr Vinod Sharma, that East Tamaki Healthcare could buy an interest in it.
He claimed he voiced concerns at that time because he knew East Tamaki Healthcare's principal Dr Kantilal Patel and his son controlled over 20 pharmacies in Auckland.
Gaur says he was assured when he signed a new lease with the joint venture firm that bought the building (now part-owned by the Sharma and Patel families) that his pharmacy would be the only one on site.
Sharma denies this and says he never would have given Gaur this sort of guarantee and that none of the leases in the building have ever contained exclusivity arrangements.
Evidence was also presented at a hearing this month about a proposal for Gaur to be involved in a second pharmacy at the premises.
Justice Gerald Nation, considering the interim injunction, said it would be a matter at trial as to why Gaur considered being involved in a new pharmacy if he honestly believed his was to be the only business of its kind at the building.
Sharma, in his evidence, said he was told that Gaur had made threats against another pharmacist who had approached the centre about the possibility of setting up there.
Gaur, in reply, denied writing the letter which contained these alleged threats and says it was a forgery.
Justice Nation said that to his inexpert eye, the signature on the letter appeared different to that on the lease which everyone agrees Gaur signed.
The judge also said that the arrangements that Sharma made with the director of the new pharmacy are "so unusual as to raise concerns as to whether Dr Sharma has been honest and forthcoming as to how those arrangements came to be and just what they are".
Justice Nation supported the injunction, saying: "On the evidence as it stands, it is likely the opening of a second pharmacy would have a significant financial impact on the profitability of Mr Gaur's company and his existing pharmacy."
See the High Court decision here: