A search operation has been launched to track down a young woman who has not been seen for five days after vanishing from a New Zealand hostel.

The family of Wickford tourist Grace Millane, 22, has issued a desperate plea for help to locate her.

Grace travelled to Auckland two weeks ago and had been in regular social media contact with her family.

But when her messages stopped Saturday and she didn't respond to birthday well-wishes the following day, her family were concerned.

READ MORE: Brother of Wickford woman Grace Millane missing in New Zealand says lack of contact is 'out of character'

In a post shared on Facebook, her brother Michael said: "Grace has been missing for five days. She has not returned to her hostel room in Auckland New Zealand and family members have had no contact since Saturday December 1.

"The Embassy has been contacted. Please share and contact if you have any information regarding her whereabouts."

Another brother Declan urged people to share the post, adding: "We haven't heard from my sister since Saturday".

The 22-year-old tourist had been staying at Base Backpackers on Queen Street in the heart of Auckland, according to Auckland media.

A missing persons report was filed on Wednesday morning and police confirmed they were investigating.

A spokesman said: "Initial inquiries are underway at this stage."

Tony McLeod, British High Commission Wellington consular manager, said the commission was aware of the missing person report.

He said: "We are working with the family in the UK and New Zealand Police in relation to reports of a missing British national in New Zealand.

"We are unable to make further comment while police are investigating the matter."

Ms Millane graduated from the University of Lincoln with a Bachelor of Advertising and Marketing in September.