(Adds details on supermarket division, cost price inflation...

(Adds details on supermarket division, cost price inflation warning)

Oct 26 (Reuters) - Australian supermarket chain Coles Group (COL) on Wednesday reported a 1.3% rise in first-quarter sales thanks to higher product prices and easing COVID-19 curbs, but warned that input costs would stay high.

Coles expects costs to accelerate in the December quarter, exacerbated by floods in the country hitting supply volumes.

The company's supermarket business, which accounts for most of the group's earnings, recorded a 1.6% rise to A$8.77 billion ($5.60 billion) but missed a UBS estimate of A$8.93 billion.

Retailers around the world have been raising prices to cope with higher fuel and ingredient costs. In Australia, the central bank has hiked interest rates six times so far this year to tame surging inflation.

The Melbourne-headquartered retailer, which operates more than 800 stores in Australia, posted group sales revenue of A$9.89 billion for the 13 weeks to Sept. 25, compared with A$9.77 billion a year ago. ($1 = 1.5662 Australian dollars)