Senior Australian Bureau of Statistics officials have warned staff of a "crisis" over the rate of return of censuses and demanded collectors increase the level of harassment of Australians, including those who can furnish evidence they have already lodged it.

Sources within the bureau have told of an extraordinary change in policy yesterday by ABS executives. On Monday, census field officers were told in writing that they did not need to return to a dwelling that had advised that the census has been completed. This included anyone who had produced a receipt number for their online census submission or who said they had done so, or who said they had posted the census form. However, citing a "crisis" in the rate of returns, ABS management yesterday told staff that they were now required to make a further visit. Householders who asked why were to be told that “it is still being investigated and [they are] still on their list requiring a visit”.