Dame Margaret died on November 11 aged 94, but news of her death was only made known on Thursday.

"Dame Margaret holds a special place in the history of our country - as the first woman in cabinet with a ministerial portfolio, the first woman senator in cabinet, and the first woman to hold a major economic portfolio," the prime minister said.

He said she opened doors for Australian women that will never be shut again.

"This is her great legacy."

Her first term in the Senate began in July 1971, retiring from her Victorian seat in June 1987.

During the Fraser government, Dame Margaret held the education, social security and finance portfolios.

A child of the Great Depression, her father died when she was 10 and her mother raised three children alone.

In the 1970s she fought for the extension of maternity leave for all women and oversaw major reform of the national child endowment scheme, switching from tax rebates to cash payments.

Treasurer Josh Frydenberg said Dame Margaret was a "trailblazer".

Australian Associated Press