Marks & Spencer's shortages of clothing and homeware could last until spring, reports say.
The retail giant will announce a rise in costs tomorrow, which would increase prices for customers if passed on.
M&S management last week said the firm was experiencing stock delays of around three weeks, according to notes from an investor event.
The firm said this was in line with other retailers, though chief executive Steve Rowe said "considerable challenges in the supply chain remain".
M&S will publish its results for the second half of 2021 tomorrow, when it will reveal more.
However, the retailer is expected to have plenty of food as the Christmas shopping rush comes.
The firm is expected to make a pre-tax profit of between £205million and £264million.
That would be an increase on the £17million loss it made in the same period of 2020 and on the £180million for the second half of 2019.
M&S has been approached for comment.
The warning to shoppers comes as retailers report supply chain disruption.
Argos said it has had to delay its Christmas toy sale by a week due to the supply chain crisis, its boss has warned.
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Sainsbury's, which owns Argos, said shipping delays in getting toys shipped from Asia to the UK are to blame.
Sainsbury’s chief executive Simon Roberts said: "On the general merchandise side, there are challenges there."
The retail boss said it would normally take 24 or 25 days to get something shipped from Asia to the UK.
This can now take more than 40 days, he added.
Roberts said: “We forward-brought a lot of container capacity, so we’re confident we will get everything through that we’ve planned for. But there are some challenges.
“Specifically, I would call out that we would normally run a toy promotion, which we have to delay this year."
The Argos boss said electronic items were a particular issue due to a worldwide shortage of microchips.
Have you noticed any shortages in stores? Let us know in the comments below
Books, toys and turkeys are all facing supply chain issues and could be in short supply at Christmas , The Mirror reported last week.
Demand for turkeys is also rising earlier than expected ahead of Christmas as shoppers brace for festive food shortages , experts warn.
Frozen turkey sales has almost doubled, according to analysts at Kantar, suggesting that Brits are stashing them in the freezer in case they can't find any closer to Christmas .
Kantar also said frozen stuffing sales are up by a fifth, while Iceland said it had seen a 400% increase in turkey sales and a three-fold hike in frozen party food purchases.
Supermarket prices surged at the fastest pace for more than a year in October amid supply chain disruption and lorry driver shortages , figures published earlier this week have shown.
The latest data from Kantar revealed that like-for-like grocery inflation rose to 2.1% in October - the highest since August last year.
Kantar said prices were rising fastest in savoury snacks, canned cola drinks and crisps.
It comes as supply chain issues in the UK and globally continue to push prices up across the board, with the Bank of England warning last week that inflation will rocket to its highest level for 10 years .
