Shoppers have begun stockpiling toilet rolls and painkillers ahead of a potential no-deal Brexit, according to Morrisons.

The supermarket’s boss, David Potts, said sales of these basic goods had risen by more than 7%. “Whether that has any bearing on how people are feeling about Brexit, I don’t know,” he said.

Potts said Morrisons had built up stocks of certain ingredients and packaging for the foods it manufactures in-house as it prepared for possible hold-ups at ports in the event of a no-deal Brexit. It has also increased stocks of “cupboard fillers” such as tins of soup and beans, reflecting similar moves by Tesco and Marks & Spencer.

But Potts said stockpiling by shoppers had so far been limited, with only a small number of customers buying extra amounts of a small range of goods.

After a good summer for supermarkets, thanks to warm weather and the World Cup success of the England football team, Potts said the “omnipresent Brexit” might have caused shoppers to become more cautious.

Sales growth at established Morrisons stores fell back to 0.6% in the three months to 3 February, compared with 1.3% in the previous three months. Potts said the slowdown was partly the result of comparison with strong sales a year before. But he added: “Consumers remain savvy and remain cautious”.

Despite the slower trading in the final three months, Morrisons increased retail sales at established stores by 1.5% in the year to 3 February, when total sales increased 2.7% to £17.7bn.

Sign up to the daily Business Today email or follow Guardian Business on Twitter at @BusinessDesk

The group increased pretax profits before one-offs by 8.6% to £406m. But lower profits from property sales and other exceptional items totalling £86m meant overall profits were down nearly 16% to £320m.

Potts said Morrisons planned to open four new supermarkets in the next year, two of which will replace ageing outlets. The group is also experimenting with putting the Safeway name on the front of a store for the first time since 2005.

Morrisons brought back the Safeway brand for products it wholesales to other retailers, including the McColls chain of convenience stores in 2017. But last week, Potts said the group had rebadged two small petrol forecourt stores with the name Safeway Daily, and it would be testing out the concept before possibly opening more.