Key Points:

"It's a phrase you hear more and more often, when you reach a certain age," says Tessa Duder of the title of her new book.

Is She Still Alive? is a collection of 13 short stories all revolving around mature women - often those trying to find a place for themselves post-family and in widowhood.

"It's always a question that's asked in tones of slight incredulity," Duder continues. "Many women disappear off the radar at a certain age.

"They can often live the last 20-odd years of their lives in relative obscurity, sometimes simply because they live longer than men, and particularly if their children and grandchildren live in a different country." The seeds of Duder's story collection - her first adult work of fiction after a hugely successful career writing for children and young adults - came in 2003 when she won the Katherine Mansfield Fellowship and spend a year in Menton, France.

"I had undertaken to write an adult novel and I thought, before I do that I'll try some short stories. It seemed like a good time and place to do that. After all, there you are writing where Katherine Mansfield wrote The Garden Party."

A couple of stories were written and quickly followed by the idea for a third, leading Duder to consider the idea of a collection based around older women.

The stories are often quite dark and moving, casting a sensitive, insightful spotlight over different lives and choices. But though Duder herself is 67 - "it amazes me to say that" - she is adamant the stories are not autobiographical. "There are sparks which have come from family stories - I've taken that and created a fictional world around it."

The only exception is Nonna, the poignant story of a widowed Italian immigrant grandmother, who, isolated by her lack of language, comes to feel "like some old cat no one can quite bring themselves to out down".

The story was triggered by Duder's earlier non-fiction book In Search of Elisa Marchetti, documenting her search for her Italian ancestors.

"That story is really the result of all the known facts I found out about her [Duder's grandmother].

"I know she came out here in 1875 and I know how many children she had and that she lost three, one of them as a 9-year-old. I know her husband died when she was about 57 and I know that she lived for another 32 years in what can be only described as some kind of house arrest. It's just so sad."

Loneliness and sadness pervade many of the stories in Is She Still Alive?, but the collection is moving rather than depressing - a tribute to Duder's deft, insightful hand.

However, talent and experience didn't prevent Duder's nervousness at writing for a new market - she even considered printing the book under a pseudonym.

Though Duder has written for adults before (including Marchetti and her acclaimed portrait of Margaret Mahy), her name is most often associated with children's and young adult fiction. She realises some people will have trouble adjusting to the idea that she can do both.

"There has been, and there will always be, those who think 'children's literature' is a contradiction. No matter how good the book. And there will be those who can't get past the idea that I am known for children's literature."

Now the short stories are out, a novel for adults is also in Duder's plans, but first her writing diary is filled with a novel set in Antarctica - the result of her inclusion in the 2007 Artists to Antarctica programme.

That book will likely be a "crossover" work - part of a trend towards books that appeal to both young adult and adult readers.

But in seeking to examine the lives and life choices of older women, Duder is introducing herself to a knowing audience - her book is about the same women who buy the most fiction, who attend writers' festivals and who form book clubs.

"I hope the very faithful woman reader might see it as a portrait gallery that they will relate to."

And in the process she may have created a new genre.

"You've heard of chick lit - we're calling this crone lit."