Tycoon Rupert Murdoch on Tuesday led memorial tributes for his mother, philanthropist Dame Elisabeth Murdoch, saying she had always taught him to understand the impact of his actions on others.

Murdoch gave the eulogy during a state memorial service at St Paul's Cathedral in Melbourne, saying while his father had been more indulgent with the family, Dame Elisabeth, who died this month aged 103, was stricter.

"She knew we started out with many advantages in life but the greatest advantage was the one she gave us all: we knew that we were loved," the 81-year-old US-based News Corp. chief told the packed cathedral.

"With mum, it was OK to stumble. She just wanted to make sure we understood the gravity of our actions and the impact our choices had on others."

Murdoch, who in the past 18 months has been under intense scrutiny in Britain over a phone-hacking scandal, described himself as a "grateful son" trying to do justice to a remarkable mother.

The media baron was forced to close Britain's 168-year-old News of the World tabloid in July 2011 in the wake of allegations that staff accessed the voicemail messages of a murdered schoolgirl and dozens of public figures.

"For mum, love wasn't something soft or mushy. It's strong and reliable. Something that brings you comfort and peace when you're lonely or troubled," he said.

The widow of Australian journalist and newspaper publisher Keith Murdoch, Elisabeth was appointed a dame for her charitable work by Queen Elizabeth II in 1963.

Patron of more than 100 charities, she was mother to four children including Rupert, Anne Kantor and Janet Calvert-Jones. Her eldest daughter, Helen Handbury, died in 2004.

Dame Elisabeth passed away at her Cruden Farm home on December 5.

The memorial was attended by a who's who of Australian society, from former conservative prime minister John Howard to comedian Barry Humphries, better known as Dame Edna Everage.