Labor MPs and former colleagues lined up to remember the trailblazing politician, after reports she had died suddenly on Sunday morning.

Current ACT Labor senator Katy Gallagher said the former frontbencher would be remembered as "the woman who led the way".

"She showed women all around Australia that not only was 'a woman's place is in the Senate' - a woman's place was at every table where the decisions were being made," Senator Gallagher said.

"A servant to the people, a passionate advocate for gender equality and for a world free from discrimination, her enormous contribution to shaping our nation will live on even though she is no longer with us."

Former Prime Minister Julia Gillard said Ms Ryan "blazed the trail for Labor women, including me".

"Every Australian's life has been improved by her leadership on gender equality," Ms Gillard said.

ACT Chief Minister Andrew Barr said her legacy in the ACT Labor party was "unheralded".

"Susan Ryan's legacy in Australian politics is immense. The Sex Discrimination Act is a significant and enduring reform that changed Australia," Mr Barr said.

"She was one of the most influential figures in Parliament House during her time as an ACT Labor Senator, and continued her fierce advocacy work as Australia's first age discrimination commissioner.

"She will be fondly remembered by those who knew her, and those that are continuing the fight for Labor values today."

Labor leader Anthony Albanese said while Ms Ryan achieved historic firsts, her legacy was the doors she opened for others.

"In a life dedicated to women's rights and equality, Susan achieved something even bigger - that while she was the first, she would never be the last," Mr Albanese said.

Ms Ryan became the first woman to serve as a senator for the ACT in 1975 after the territory gained a second Senate seat.

She campaigned on the slogan, "a woman's place is in the Senate".

She later became the first woman to become a minister within the Hawke government.

Her first speech noted as a female parliamentarian, she was part of a "a particularly small minority group".

"In this respect, our national Parliament is a microcosm of our society. Women are as badly under-represented here as they are anywhere else in our society where power resides or where decisions are made," she said.

She argued, "improvements in education, training, legal aid services, welfare services and childcare benefit the whole of society and not just women".

She attracted controversy in 1978, after attempting to overturn a legislative instrument to stop abortion clinics being set up in the ACT.

She told the parliament the move thwarted the clear wishes of the people of Canberra, as an ACT Legislative Assembly inquiry recommended that a special abortion clinic be set up in Canberra under the control of the ACT Health Commission. The motion was defeated and Ms Ryan received thousands of abusive phone calls, and even death threats.

In 1981, she introduced a private senator's bill to outlaw sexual discrimination. While the bill did not pass, it laid the foundations for the landmark Sex Discrimination Act she introduced as a minister in 1983, which outlawed discrimination on the grounds of sex, marital status or pregnancy.

She called the legislation, "probably the most useful thing I've done in my life".

In 1986, she introduced affirmative laws to boost women's participation in the workforce.

She served in the Senate until 1987 and later became Australia's first age discrimination commissioner in 2011. She also served as disability discrimination commissioner in 2014.

In 2017, she was awarded an honorary doctorate from the Australian National University for her contribution to the advancement of human rights, as the Me Too movement was taking off.

She told The Canberra TImes at the time she was deeply distresed at the "epidemic" of sexual harassment faced by working women today.

"I feel more than disappointed, deeply distressed that women are still battling things that they shouldn't have to battle," she said.

"Women need to act collectively and support each other on these big issues."