In extracts from the biography, published in The Bulletin magazine today, Mrs Whitlam says Mrs Howard does not do enough charity work or public appearances.
"She is useless in terms of how little she really gives the community," Mrs Whitlam is quoted as saying in the book due out next week.
"She doesn't even go to the old people's homes that Howard visits. The only thing she goes to is big public things. There's Howard shaking hands and kissing old ladies in retirement homes. If you've got a wife, your wife should be there, too.”
"You have certain obligations to make the most of the position, to accept invitations, to support charitable causes, to let yourself be known to the people of Australia. I mean, people want to see you. What is she hiding?"
Mrs Whitlam questioned what else Mrs Howard had to do. "What on earth does she do with her time?" she says.
Mrs Howard’s recent engagements include a fundraiser for a youth charity last Friday, a private lunch in support of cancer research organisation Centenary Institute on Monday, and a dinner hosted by the National Breast Cancer Foundation on Tuesday.
She is also the patron of the National Breast Cancer Foundation, the National Portrait Gallery and the Australian women's hockey team, the Hockeyroos.
No humour
Mrs Whitlam says she also fears Mrs Howard lacks humour. In the biography she tells the the story of how the two women met at a party in the 1980s, shortly after Mr Howard dethroned Andrew Peacock as Liberal Party leader.
Mrs Whitlam tried to break the ice with a joke. "Congratulations on John's acquisition of office - or should I say, commiseration?" she offered.
She said Mrs Howard "visibly bridled and said, ‘You don't commiserate with somebody who's got what they always wanted'."
"I thought, you silly person. No sense of humour, whatsoever," Mrs Whitlam said.
She also described Mrs Howard's failure to acknowledge a gift from the couple as “inexcusable behaviour".
Mrs Whitlam donated a "very handsome silver box from Mexico" following a request from Mrs Howard for an item that had been given to the Whitlams for display in The Lodge or Kirribilli House.
Mrs Howard never responded, Mrs Whitlam said, leaving it to the chairman of the Australiana Fund to respond 10 months later in a letter addressed to her husband.
Holding hands
And Mrs Whitlam, whose husband Gough was prime minister for three years in the early 1970s says Mrs Howard has no sense of humour and should not still be holding hands with her husband in public.
"For God's sake, they've been married for over 30 years!" Mrs Whitlam says in a new biography to be published next week.
Mrs Howard declined to comment on the criticism but her husband says he will continue to hold hands with his wife.
Mr Howard refused to say if he found Mrs Whitlam’s comments hurtful. "In the time that I have been prime minister, Janette and I have always given full respect to Gough and Margaret Whitlam as a former prime minister and his wife, and I don't have any further comment to make," he told reporters.
But Federal Treasurer Peter Costello told Southern Cross Radio that Mrs Whitlam should keep her opinion to herself.
"I don't know why Margaret Whitlam has decided to say what she has. My advice to Margaret Whitlam would be, if she has opinions, to keep them to herself."
Labor leader Kim Beazley has refused to buy into the row saying he doesn’t comment on politician’s wives.
Better relationships
Mrs Whitlam said she had better relationships with other wives of prime ministers, describing Dame Enid Lyons as talented and admirable and Betty Gorton as good fun.
She said she always felt "rather like a large plum dropping off a tree at the wrong moment" in Dame Pattie Menzies' company.
But she warmed to Tamie Fraser, despite her "rather twee voice when she was young", saying she had had a few giggles with her.
Zara Holt and Hazel Hawke also had good senses of humour, but Mrs Whitlam said she did not have much in common with Annita Keating.
Of Mrs Howard, she said: "I fear she's a steely woman."