The "devastated" mother of missing Auckland escort Carmen Thomas wants to come to New Zealand to help search for her daughter.

Theresa Lavagna contacted police from her South African home as soon as she learned her daughter had vanished.

She was told of the disappearance by her sister in Britain, Carol Lavagna.

"All she knows is [police] are talking to all her friends," Ms Lavagna said.

Her sister was not coping well with the news. "She's absolutely devastated. She wants to go to New Zealand."

South-African born Miss Thomas, 32, hasn't been seen since July 1. The last known contact from her was a text sent to her boss two days later.

Her black Nissan Pulsar was discovered abandoned in Hamilton and her bank accounts haven't been touched.

Miss Thomas shared custody of her 5-year-old son, Jack, with her former partner.

The last contact any of the family had with Miss Thomas was when she spoke to her mother in June to say she was unwell and in hospital.

The family are pleading for her safe return. They can't understand what might have happened as she had plenty of friends and family she could have reached out to if something was wrong.

Ms Lavagna said Miss Thomas had moved around a fair bit, first meeting a man in Australia -a relationship which didn't last - before moving to New Zealand, where she meet Jack's father.

She said it wasn't uncommon for family not to hear from Miss Thomas for a while.

"I think she's got wandering legs, that's the kind of person she is. You can go for a few weeks or a month and you wouldn't hear from Carmen but she always pops up.

"She's never been the sort of person to do that [vanish]. I just hope she's all right."

Her family had all meet Miss Thomas' son Jack, who she was devoted to.

"He's an absolutely beautiful child ... never on earth would she ever leave Jack. It's just completely out of character to leave Jack the way she has, it's just not Carmen.

"We just want to find her and we want her back where she belongs. Jack needs her."

Friends and family are using Miss Thomas' Facebook page to beg for information.

Sandra Gurney, her best friend from high school, who is based in Britain, said: "We are all so worried here in England. Please just the smallest bit of information that you can give us would be really appreciated.

"Someone really MUST know something. She was a devoted Mum and a fab friend. Love you Carmen xx."

Another friend Liam Ryan wrote: "Hoping for a safe return - this is so out of character for such a devoted mother. Am in complete shock."

Acting Detective Inspector Mark Benefield yesterday renewed his appeal for anyone who had seen Carmen or her car, registration number ATS209, to come forward.

Police were back at her Remuera house yesterday searching for clues that could explain her disappearance as well as reviewing CBD security surveillance footage that may be relevant to the inquiry.

Anyone with information should call 0800 537 735 or Crime Stoppers 0800 555 111.