Despite the downgrade, Victoria still added more people than any other state between 2006 and 2011, growing by 408,000 or 8 per cent. NSW added 395,400 people, growing just 5.8 per cent.

By contrast, the census found slightly more people than expected living in WA, Tasmania and the territories.

Based on the census findings, the bureau estimates that at June 30 last year, Queensland had 106,000 fewer residents than earlier reported. NSW lost 91,000 people, Victoria 87,000, and South Australia 18,000.

The bureau will spend the next year working out what was wrong with its earlier estimates. In an explanation yesterday, it gave several possible reasons, including errors in the 2006 census figures, or in the records of births and deaths, or in estimating the real size of net overseas migration.

Yesterday's figures are only preliminary, with final post-census results to be released in a year's time. The bureau next month will publish revised estimates of city and regional populations, which are likely to slash population estimates for the main cities, other than Perth.

Its updated figures show WA streaking ahead in population as well as economic growth. By the end of December, Australia's population had edged up to 22.5 million, growing by 1.4 per cent, but WA was growing at more than twice that rate.

Victoria again had the biggest growth in numbers, its population rising 75,400 or 1.4 per cent, while New South Wales grew by 71,000 or 1 per cent. On December 31 NSW had an estimated 7,250,000 people, and Victoria 5,575,000.

Net emigration from NSW to other states jumped in 2011, from 11,240 to 16,100. Victoria again had slightly more people arriving than leaving, a net 3330 from other states. The main shift was to Queensland, which gained a net 9600 people, and WA, a record 8460 net arrivals from the rest of Australia.