Coles managing director Leah Weckert says big box retailers should use a Senate inquiry this week to show that “they are working to provide value to customers”, even as the supermarket giant rewarded shareholders with a bigger payday and higher margins at the same time as political scrutiny in profits intensifies.

The country’s second-largest grocery chain reported a 4.4 per cent rise in revenue to $43.7 billion in the 53 weeks to June 30, while earnings rose 8.2 per cent to $3.7 billion, sending Coles shares to a two-year-high.