Leading constitutional historian Dr Helen Irving has called for vigorous debate on, and a redefinition of, the meaning of Australian citizenship as the country approaches its Centenary of Federation.

Dr Irving, author of To Constitute a Nation: A Cultural History of Australia's Constitution, and a senior lecturer at UTS, identifies three models of citizenship in Australia since 1901 - "protectionist", "expansive nationalist" and "protective internationalist".

In her recent public research lecture at UTS she proposed that a fourth model, "expansive internationalist", should be embraced as Australia enters the 21st century.

"In 1901, Australians were British subjects and did not have legal citizenship until almost 50 years later. Despite this, at the time of Federation there was a strong sense of separate 'citizenship', which could be called 'protectionist', built around restricted immigration, tariffs and industrial arbitration."

Dr Irving says that following the Second World War, the restrictive character of Australian citizenship was successfully challenged. "Australians gained legal citizenship and simultaneously brought in a greatly expanded immigration program, with a cultural program designed to 'assimilate' the new immigrants into full Australian citizenship.

"The Jubilee of Federation was celebrated in 1951 in a spirit of expansive, nationalist optimism, and in the following 40 years, formal citizenship eligibility and entitlements were adjusted, and the concept of multiculturalism was introduced," she said.

In 1992, further significant steps were taken with the Keating Government's commitment to a republic and with the High Court's dramatic overturning of the doctrine of terra nullius and its finding of implied rights and freedoms in the Constitution.

"These developments completed the evolution of the 'protective internationalist' model of Australian citizenship."

Dr Irving said that with the Centenary of Federation approaching, there is an opportunity to reinvigorate Australian citizenship with the optimism of the Jubilee years.

"I see a crucial dimension of a new 'expansive internationalist' citizenship as being an expanded immigration program linked to regional redevelopment and cultural initiatives," she says.

Dr Irving is editor of A Woman's Constitution?: Gender and History in the Australian Commonwealth, and is currently editing The Centenary Companion to Australian Federation, to be published next year. She is a council member of the Constitutional Centenary Foundation.