British shoppers have been warned they could struggle to find tea on the shelves due to “supply issues” facing supermarkets.

Sainsbury’s has cautioned shoppers in some stores that there are “nationwide” problems which could impact the availability of black tea.

But retail bosses have said the problems are “temporary” and stressed that the impact on consumers is expected to be “minimal”.

A sign in one Sainsbury’s store read: “We are experiencing supply issues affecting the nationwide supply of black tea. We apologise for any inconvenience and hope to be back in full supply soon.”

Sainsbury’s has been contacted for comment.

It is understood that the supply problems, which are partly linked to disruption of shipments through the Red Sea, are specifically linked to just one supermarket tea supplier.

Andrew Opie, director of food and sustainability at the British Retail Consortium (BRC), said: “There is temporary disruption to some black tea lines, but the impact on consumers will be minimal as retailers are not expecting significant challenges.”

Tea is largely produced in Asia and East Africa, with China, India, Sri Lanka and Kenya producing around three-quarters of tea globally.

Freight shipments from these regions have faced major disruption over the past two months due to attacks in the Red Sea.

Violence by Houthi rebels in the region caused most shipping firms using the key trade route, which heads towards the Suez Canal, to redirect shipments around the Cape of Good Hope at the foot of Africa.

This adds roughly 10 to 14 days onto shipment times, as well as increased costs for shipping firms.

Sparsh Agarwal, owner of several tea gardens in Darjeeling in India and founder of Dorje Teas, told the i newspaper in December, that tea shipments were being stalled due to the disruption.

“We sent shipments to the US and Europe two weeks ago, but they are still in Bombay port and have not been picked up yet,” he told the newspaper at the time.

Joint strikes from the US and UK have been launched on the Yemen-based Houthis in recent weeks in a bid to stop the recent wave of attacks.