1920 New Zealand receives League of Nations mandate to govern former German territory of Western Samoa.
1920 First aeroplane flight across New Zealand's Cook Strait.
1920 Farmers form the Australian Country party in Melbourne.
1921 Western Australian Edith Cowan becomes the first female member of an Australian parliament.
1921 The Archibald Prize for Portraiture is bequeathed by Bulletin founder J.F. Archibald. In 1943 a controversy ensues when William Dobell is accused of caricaturing Joshua Smith.
1922 Outback aviation company the Queensland and Northern Territory Aerial Service (Qantas) starts regular passenger flights.
1922 Queensland becomes the first Australian state to abolish capital punishment. Victoria is the last, in 1975.
1923 Dr Cyril Callister invents a savoury yeast spread called Vegemite in Melbourne.
1924 Voting in Australian federal elections is made compulsory.
1926 An Imperial conference in London announces that Australia and New Zealand will be self-governing dominions.
1927 Melbourne underworld leader "Squizzy" Taylor is shot dead in a pistol duel with a rival gangster.
1927 Australian federal Parliament moves to Canberra from Melbourne.
1928 The Australian Inland Mission and Qantas launch the Flying Doctor Service.
1928 Australian aviators Charles Kingsford Smith and Charles Ulm make the first flight across the Pacific, the first non-stop flight across Australia and the first flight across the Tasman Sea to New Zealand, all in the Southern Cross.
1931 Despite opposition from King George V, Sir Isaac Isaacs becomes the first Australian-born Governor-General.
1931 An earthquake at Napier, New Zealand, kills 256 people.
1932 The Sydney Harbour Bridge is officially opened. Former army officer Francis de Groot is fined for "having maliciously injured a ribbon," rushing forward on horseback to slash the official tape with a sabre before it could be cut by NSW Premier Jack Lang.
1932 Champion racehorse Phar Lap dies mysteriously on a California farm. He is returned to Australia, stuffed, mounted and displayed in a glass case in the Victorian Museum.
1932 Australian schoolchildren sing the virtues of Aeroplane Jelly after Les Woods' jingle airs on commercial radio.
1933 Outback aviation company the Queensland and Northern Territory aerial Service (Qantas) starts regular passenger flights.
1933 The English cricket team wins the Ashes series using the controversial "bodyline" bowling technique.
1933 Nursing sister Elizabeth Kenny sets up her first polio clinic in Townsville, Queensland. A royal commission four years later condemns her methods.
1935 The giant, poisonous cane toad is introduced into Queensland to control the grey-back beetle, a sugarcane pest. The toads become an environmental disaster.
1935 Chef Bert Sachse, at Perth's Esplanade Hotel, adapts a New Zealand meringue cake to create the pavlova in honour of former guest and ballerina Anna Pavlova.
1936 National Party formed in New Zealand by Coalition MPs.
1936 The last Tasmanian tiger in captivity dies at the Hobart zoo. The marsupial is presumed to be extinct.
1936 Working week reduced from 44 to 40 hours in New Zealand. Most Australian workers wait another 12 years to gain 40-hour week.
1937 Hubert Opperman cycles from Perth to Sydney in a record 13 days.
1937 Dad and Dave, a radio serial about rural Australia, begins; runs until 1953.
1938 Aboriginal artist Albert Namatjira sells all 41 landscape paintings at his first exhibition in Melbourne.
