The Australian Bureau of Statistics will have to start cutting its key economic and population reports and leave the government and Reserve Bank in the financial dark if it is forced to absorb any more budget tightening, the nation's top statistician has warned.

David Kalisch, releasing the bureau's 2018-19 annual report which showed the agency recording a $46.2 million loss, said the ABS had suffered a 30 per cent reduction in operational funding over the past decade.

Retiring national statistician David Kalisch says the ABS will have to start cutting key economic data releases without extra funding. Credit:Alex Ellinghausen

The cumulative cuts, at a time when demand for information and data was growing sharply, were a "conundrum" for the ABS which had already cut non-essential surveys and releases. More important data, used extensively by all levels of government and the Reserve Bank, were now at risk.

"While the ABS is more efficient and effective than it was previously, funding cuts of this level inevitably reduce the service we can provide for governments, business and the community," he said.