Iran does not publish official statistics on the number of people it executes. (Representational)

Iran has executed a nurse convicted of murdering a six-year-old boy, the judiciary's official news agency reported on Sunday.

The woman was found guilty of carrying out the murder in June 2016 while working for the boy's grandmother at her home in Kelardasht city, in the northern province of Mazandaran.

The nurse was sentenced to death a year later.

She confessed to the premeditated murder and said she did it out of "anger", the prosecutor said, quoted on Sunday by the Mizan Online news agency.

"The verdict was finalised as it was not appealed," the prosecutor added.

The executed woman was not identified in the report. She was in her early 40s.

Iran does not publish official statistics on the number of people it executes.

But according to Amnesty International, while secretive China is the world's "leading executioner", Iran had the highest known figure in 2018 with at least 253 people put to death, down from 507 in 2017.