"I reached out to the Registrar-General himself, asking if there are any restrictions naming babies after band names, or albums," Farrier wrote.
He quoted Registrar-General Jeff Montgomery as saying: "There are no restrictions on naming babies after bands or albums, as long as the word used is not generally considered to be offensive or does not resemble an official rank or title."
Farrier suggested that the kids should be given tickets to the bands' gigs for the rest of their lives and said he had reached out to the metal legends.
He also included a photo of the proud mum, writing that "she deserves our complete and utter respect".
Last year nearly a quarter of baby names declined by the Department of Internal Affairs featured the word "Royal".
The Registrar-General of Births, Deaths and Marriages' 2020 rejection list showed
Roya Ltee, Royal, Royal-Blue, Royal-Reign, Royalty, Royalty-Rain, Royele-Blue, and Royell are among the 44 names shot down.
The guidelines make sure names don't cause offence, are a reasonable length, and don't resemble an official title or rank.
Nobody tried to call their newborn Covid-19 ... but it would've been rejected anyway, in case it causes offence.
In 2008, Family Court Judge Rob Murfitt ordered that a girl named Talula Does The Hula From Hawaii be taken into court custody so she could change her name. It had not been registered in New Zealand, but other names such as Violence, Chardonnay and Number 16 Bus Shelter had been.