The Australian gold rushes were periods of significant immigration of workers, both more locally and from overseas, to areas which had discoveries of gold deposits. A number of gold finds occurred in Australia prior to 1851, but only the gold found from 1851 onwards created gold rushes. This is mainly because, prior to 1851, the colonial government of New South Wales (Victoria did not become a separate colony until 1 July 1851, and Tasmania did not become a separate colony until 1856) had suppressed news of gold finds which it believed would reduce the workforce and destabilise the economy.