Ex-Carrefour France boss Rami Baitiéh became Morrisons CEO in November, succeeding industry veteran David Potts.
"There are so many great strengths at Morrisons but I must also be very direct," he told reporters after the group published results for its 2022/23 year.
"Since the pandemic, Morrisons has not been on peak form, our market share has slipped, slowly but consistently, our like-for-likes (sales), although on an improving and encouraging trend now, have been below the pack for a while, and the switching data has not been encouraging," he said.
"So although we have many structural, operational and cultural strengths, we must not be satisfied with our recent performance."
He said he was working on plans to address the situation, with a focus on listening to customers and staff.
Baitiéh said Morrisons no longer held major meetings without input from customers, and every store had two "customer round tables" a month, with struggling stores having one every week.
He is also holding online meetings with Morrisons' top 100 people every evening, six days a week.
"Already we are making progress, change is underway at Morrisons," he said.
(Reporting by James Davey, Editing by Paul Sandle)
By James Davey
