The former Council of Trade Unions president, who has terminal cancer, had her bid to use cannabis oil stalled by the Ministry of Health.
The application contained "insufficient information to enable a decision to be reached" and has been deferred.
An online petition is asking for Associate Health Minister Peter Dunne to reconsider the decision, saying Ms Kelly needs help to control her pain and nausea.
So far more than 2400 have signed it, but the organiser who did not want to be identified is hoping for 5000 signatures.
"Helen Kelly has done so much, for so many in New Zealand, this is the least we can do for her," the petition reads.
Labour MP Damian O'Connor is drafting a private member's bill to allow the medicinal use of cannabis.
He has agreed to present the petition to Mr Dunne, saying that while the minister has to consider all of the advice he's given, sometimes hard decisions have to be made.
Mr O'Connor says this is a case where Mr Dunne has discretion but "unfortunately he's disappointed".