SHONA Robertson won't let a little thing like nerves stand in her way before addressing possibly the biggest audience of them all: The United Nations General Assembly.

Ms Robertson, 35, will address the world forum in Geneva on Tuesday, to mark World Down Syndrome Day - an event she and her mother, Penny Robertson, helped establish six years ago at the UN Headquarters in New York.

This year's event is the first time World Down Syndrome Day will be celebrated at the UN in Geneva, with self-advocates from around the world due to meet with international policy makers, including mission representatives at the UN Human Rights Council and members of the UN Committee on the Rights of Persons with Disabilities.

Shona, who lives independently in Tweed Heads, said she was looking forward to the trip, despite being nervous of flying.

"I'm happy to represent Australia and our country,” Shona said.

"I'm going to represent people with disabilities in our country.”

The trip follows years of activism for the rights of people with Down Syndrome by Shona and her mother, who helped co-found support group Down Syndrome International in 1993.

"I've seen a lot of changes, my mum is the best,” Shona said.

Mrs Robertson, a geologist by trade before becoming a lecturer and teacher, pioneered education for children with a disability in Indonesia, setting up the Australian International School after she was unable to find a mainstream school for children with a disability in Jakarta.

In addition to addressing the UN General Assembly, Shona will participate in an open dialogue session on the rights of people with a disability. She is an author and has spoken at several conferences around the world on living in the community, her education, employment opportunities and the lack thereof.