Veteran children's TV star Simon Townsend has died aged 79, shortly after being diagnosed with an aggressive form of cancer.

The former newspaper and TV journalist launches The Amazing World of Simon Townsend! Appeared on Channel Ten in 1979 with mascot Woodrow the Bloodhound. The groundbreaking show made him a household name in the 1980s, delighting young audiences with magazine-style stories that covered a wide range of topics including mental health, bullying, grief, social justice and war.

He always ended by saying, "Remember, the world is a beautiful place."

"Wonder World" ran until 1987 and aired nearly 2,000 episodes, winning five Logie Awards and 10 episodes of outstanding ratings.

Townsend's family confirmed he died on Tuesday.

"In his final days, Simon was surrounded by family, journalists, writers, actors, political activists and Italians," his family said.

“The conversation was loud, passionate and full of laughter until the end.”

Townsend, a well-known conscientious objector during the 1967 Vietnam War, made headlines when he spent 28 days in Long Bay Prison.

When he was drafted into the Army, Townsend refused to accept orders that "the war would stop when people refused to fight," according to his family.

He later found himself at loggerheads with broadcasting authorities as he pushed for programs that never spoke down to children.

"Simon often found himself at loggerheads with Australia's children's television regulator, struggling to maintain the boundary-pushing ethos of his show and maintain TV ratings for his children," his family said.

Television and radio host Amanda Keller, who worked as a researcher at Townsend, posted her condolences on social media.

“I was a researcher there and was lucky enough to work with some of the most talented people of my generation,” she said.

"Many of my closest friends today were from that era. I will be forever grateful to this show, and to the seminal power of Simon Townsend."

Journalism is in his blood. His father, Lewis Townsend, was the deputy editor of the Sydney Morning Herald. Simon left school at 15 to work as an intern at the Central Coast Express in Gosford.

He began his television career as a reporter on ABC's "This Day Tonight" and later collaborated with Mike Willesee on "A Current Affair."

Following Wonder World, Townsend created an entertainment program for ABC TVTV, which launched in 1993.

TVTV features interviews and commentary with television personalities. The original Wonderland line-up included Edith Bliss, a journalist, and musician and broadcaster James Valentine.

Townsend suffered a series of strokes in his later years.

He is survived by three children, Lisbeth, Michael and Nadia, five grandchildren, Rex, Lenny, Laura, Ollie and Auggie, and brothers David and Stephen.