Australian group Wesfarmers has tried to appease shareholder concerns about the turnaround of grocer Coles just a year after its acquisition.

Wesfarmers’ shares tumbled after shareholders questioned the company’s ability to refinance debt and revive struggling Coles, and voted against Wesfarmers’ remuneration package at its AGM last week.

Wesfarmers chief executive Richard Goyder told shareholders the turnaround of Coles would continue as planned, in spite of the downturn. “The changes we need to make at Coles are entirely within our control and need to be made regardless of external conditions,’’ he said.

In October Wesfarmers said capital expenditure would be slashed from Aus$2 billion to less than Aus$1.8 billion (£860.2 million to£774.2 million) this financial year and a big tranche would be spent improving Coles.

Goyder said “some green shoots of improvement” were evident at Coles, with on-shelf availability improving and a cut in central costs. He added that sales had “improved” in October but did not provide details.

Wesfarmers’ Aus$22 billion acquisition of Coles in November last year made it Australia’s biggest retailer. Following the deal, Wesfarmers drafted in Asda saviour Archie Norman to advise on Coles’ turnaround.

Goyder said concerns about Wesfarmers’ debt levels were “unfounded” and that it had refinanced Aus$800 million (£344.1 million) of debt in the first two weeks of this month.