Tributes for a "lion of a man" filled with poignant and lighthearted moments flowed today at a memorial service for the art critic and literary great Robert Hughes.

"Thank you, Robert, for your contribution to the country you were born in and the world we live in," his actor cousin Bryan Brown said in a faltering voice after reading from Hughes's best-known book, The Fatal Shore.

A procession of speakers at the Art Gallery of NSW including Hughes's family members, barrister Charles Waterstreet and journalist Jennifer Byrne told colourful stories from the life of a critic described as without peer.

Barrister Tom Hughes, QC, told how, as a two-year-old, "my dear brother" took a liking to a topee hat worn as protection from the sun.