22/04/2017 1:18 PM AEST | Updated 24/04/2017 1:59 PM AEST

Sydneysiders Join Global March For Science Protest

A pro-science crowd has filled Martin Place.

A major pro-science rally is underway in Sydney as part of a worldwide day of action aimed highlighting the need for stable investment in science.

The March for Science event in Sydney's CBD is one of 500 events across the globe on Sunday to urge more science education, open communication of scientific findings, and evidence-based public policy.

Speakers at the rally, which kicked off at 12.30pm local time, include former federal Liberal leader John Hewson, broadcaster Julie McCrossin and science academic Angela Maharaj.

"At a time when science is most important to the development of our society, the gap between the public and science is unfortunately widening," Hewson said.

March for Science bills itself as a grassroots movement that champions adequately funded science "as a pillar of human freedom and prosperity".

It began as a single event in Washington DC, with supporters in 54 countries now hosting marches to coincide with Earth Day.

Protests are also underway overseas.