Why did they let immigrants to the Australia gold rush?

There was no policy of allowing or excluding immigrants to Australia due to the gold rush. The gold rush was a spontaneous event that encouraged many people to seek the fortune. People from all over the world came to Australia in hopes of striking it rich. However, the Australian authorities did attempt to regulate the influx of immigrants, implementing policies such as the White Australia Policy, which favored European settlers, the gold license fee, the Chinese poll tax, and quarantine measures to control disease.