Australian consumers are still cautious with their money.
Spending fell 1.9 per cent in December, seasonally adjusted, according to Commonwealth Bank's business sales indicator (BSI).
After a rise of 2.4 per cent in November, it reflects the volatile trend for spending throughout 2012.
But while seasonally-adjusted spending was weak, the more stable trend estimate rose 0.3 per cent in December, after also rising 0.3 per cent in November and 0.4 per cent in October.
CBA local business banking general manager, operations and sales strategy, Lex Thornton said Australians still seemed reluctant to spend.
"Although the overall economic picture showed signs of improvement in the latter half of 2012, consumers are still proceeding with trepidation," he said.
"If consumers remain prudent, it is unlikely that we will see any consistent or significant spending trends form in the near future.
"For 2013, it is important that businesses make sure they have solid processes and plans in place to navigate future volatility."
Of the 20 industries included in the BSI study, transportation was the strongest performer, rising 1.8 per cent in December, while government services rose 1.4 per cent in trend terms.
However, 12 sectors contracted, with service providers, hotels and motels and automobiles and vehicle rentals the weakest - down 3.6 per cent, 1.0 per cent, and 0.9 per cent, respectively.