National Insurance was a planned system of social security in Australia which would have provided medical, disability, unemployment and pension coverage to its contributors and their dependents. The scheme was passed into law by the Lyons government as the National Health and Pensions Insurance Act 1938, but was abandoned the following year in order to divert funds to defence.

There were few serious proposals for a comprehensive social insurance scheme in Australia before World War I, as it was seen as unfeasible. In 1911, deputy opposition leader Joseph Cook told federal parliament that "the more I think of it the more convinced I am that we must come ultimately to a form of national insurance which will give every man–the millionaire as well as the poor man–who has subscribed to his own insurance fund the right to receive that insurance, without taint of pauperism or charity, in his old age".

Advocates of greater federal government involvement in healthcare were divided between those who supported centralised public health services providing universal healthcare and those who supported contributory insurance-based schemes.

At the 1922 federal election, the Country Party's platform included plans for a national insurance scheme covering "sickness, unemployment, poverty and age". After the election the party's leader Earle Page, a trained surgeon and strong supporter of the scheme, entered into a coalition with the Nationalist Party under S. M. Bruce, who became prime minister. In 1923, the new government announced plans for a comprehensive social services system that would "remove altogether the taint of pauperism". It subsequently established the Royal Commission on National Insurance under the chairmanship of Nationalist senator John Millen, which ran from 7 September 1923 to 5 October 1927.

In September 1928, Page introduced the National Insurance Bill into the House of Representatives, which "provided for sickness, old age, disability and maternity benefits, mainly paid for by compulsory contributions by workers and employers, along with smaller payments to parents of children under 16 and to orphans". The legislation failed to pass before the 1928 federal election, although the government heavily promoted the scheme during the election campaign. The scheme was postponed indefinitely the following year, prior to the government's parliamentary defeat on a no-confidence motion and defeat at an early election.

The Lyons government, a coalition between the United Australia Party and Australian Country Party, was re-elected at the 1937 federal election on a platform which included a national insurance scheme covering both old-age pensions and healthcare. The strongest advocates of national insurance within the UAP were treasurer Richard Casey and former minister Frederick Stewart, while Prime Minister Joseph Lyons was lukewarm towards the idea and many Country MPs were hostile.

The government's legislation was largely modelled on its British equivalents and was drafted by British civil servants. However, unlike in the UK, administrative control over the scheme was to be vested in a National Insurance Commission. Its final form was largely due to financial considerations, with the legislation required the scheme to become self-financing as soon as possible. It ultimately included contributory schemes for sickness and disability, old-age pensions, payments for widows and orphans, and child endowment. Many specialist medical services were excluded from the scheme, including anaesthesia, pathology, x-rays, venereal diseases, abortions, miscarriages and stillbirths. The health and pension insurance components (known as the Kinnear scheme after their author) were to be enacted separately to the unemployment insurance component.

Although the Australian branches of the British Medical Association (BMA) were largely in favour of a contributory health insurance scheme, the medical profession ultimately came into conflict with the government over the scheme. The initial conflict was over the size of the capitation fees payable to doctors, with general practitioners claiming they would have to increase their workload in order to maintain their income.