In a statement, Judge Deborah Marshall said she had been aware of "ongoing speculation" about the cause of death surrounding the teenager.
"Based on the information available to date, it does not appear that the death in question is linked to the Pfizer COVID-19 vaccine," she said.
"However, this issue will be investigated carefully by the coroner and pertinent information will be requested from various agencies, including the COVID-19 Vaccination Independent Safety Monitoring Board."
Judge Marshall said it could be "a number of months" before the final post-mortem report is received.
"The coroner's findings in relation to this point will be made available once the inquiry has been completed."
To date, Judge Marshall said only one death has been associated with the COVID-19 vaccine.
Last month, a woman died due to myocarditis, a rare side effect of the Pfizer vaccine.
Photo/RNZ Caption: Chief coroner Judge Deborah Marshall