Consumers splashing out on cars and getting into the festive spirit bumped up economy-wide spending in December but times are still tough for retailers, who suffered their worst result in more than six years.

The Commonwealth Bank Business Sales Indicator (BSI) shows spending increased by 0.4 per cent in trend terms in December compared with the prior month.

CommSec chief economist Craig James said the biggest boost came from the cars and vehicle sector, which rose 1.7 per cent.

“The record sales we saw in 2017 can be largely attributed to improved affordability, making it more attractive for Aussies to purchase a new car,” he said.

Spending on amusement and entertainment grew by 1.2 per cent, which was the fastest growth rate for six months.

“It seems like Aussies really got into the festive spirit,” he said.

But spending at retail and clothing stores remained soft, down by 0.4 per cent in trend terms in December – the weakest result in six-and-a-half years.

The BSI measures the value of credit and debit card transactions processed through the bank’s merchant facilities.

The December result marks the 35th consecutive monthly lift in sales.

On a seasonally adjusted basis, the BSI fell for the first time in five months in December, falling 0.4 per cent after gains totalling 2.4 per cent over the previous four months.

In yearly terms, all but two of the 19 industry sectors covered recorded gains, with spending down at mail order/telephone providers (falling 5.5 per cent), followed by retailers (0.4 per cent weaker).

Sectors with strongest annual growth in December included service providers (up 15 per cent), amusement and entertainment (also up 15 per cent), utilities (13.6 per cent stronger) and airlines (up 12.7 per cent).

Access exclusive analysis, locked news and reports with Inside Retail Weekly. Subscribe today and get our premium print publication delivered to your door every week.