"There's a difference between needing diplomatic immunity when our diplomats have been sent to parts of Asia or Africa which are dangerous, as opposed to dealing with friends here.
"Friends should not abuse the system. That is not what it's designed to do, to allow people to skip paying rent."
The Tenancy Tribunal ruled last month that Tvarozkova owed her Wellington landlord $20,000 in unpaid rent and damaged property.
However, the tribunal did not consider her automatic immunity as a diplomat. A hearing has been scheduled for next month to re-examine the matter.
Meanwhile, Mfat has twice asked for immunity to be waived.
Failure to do so would have a broader effect on the diplomatic corps in New Zealand, Gillespie said.
"It's not just a bad look in terms of the reputation of the EU if they refuse to waive it, it will have a spill-over effect for all the diplomats in Wellington and Auckland because people will start questioning whether their tenancies or legal arrangements are secure."
Mfat first asked for a waiver late last month, when it first became aware of the tribunal ruling. It reiterated its request earlier this week.
Gillespie said approval for a waiver would have to come from Brussels, which could take some time.
The case was unusual in that diplomatic immunity matters were usually dealt with behind closed doors and before any court ruling was made.
"If it was a criminal matter, the police would become involved, the police would get hold of the diplomat, the diplomat would ring up the embassy and it would be dealt with.
"Somehow this has managed to get through the practice of trying to keep these things behind closed doors. I suspect it wasn't intentional, it was probably because someone wasn't notified."
The landlord, Matthew Ryan, has said he is angry that the diplomat is being protected and frustrated that he is out of pocket.