Diageo, the world's largest spirits company, said sales had risen so far in its new fiscal year, but that foreign exchange rates were increasingly eating into its operating profit. 

The maker of Guinness, Smirnoff vodka and Johnnie Walker whisky said sales volume has grown by a mid single-digit rate.

It said this reflected improved growth trends and an easy comparison with a year-earlier period that saw weak performance, particularly in the US. 

"The year has started well and performance is in line with our expectations," Diageo's chief executive Ivan Menezes said in a statement today. 

Diageo North America expects first-half net sales to fall 2%, however, as comparisons get tougher. 

At current rates, currency weakness should reduce Diageo's operating profit by £150m in fiscal 2016, compared with a prior forecast for a £100m hit.