Tesco has joined other supermarkets in limiting the number of boxes of eggs customers can buy as the impacts of rising costs and bird flu continue to take their toll.

The shopping chain said it had introduced a temporary buying limit of three boxes per customer as a precautionary measure.

Earlier this month, Asda and Lidl announced limits on egg purchases at some of their stores.

The National Farmers’ Union (NFU) has called for an “urgent investigation” into the egg supply chain disruption.

The NFU said the Department for Environment, Food and Rural Affairs (Defra) should look into whether a declaration should be made under the Agriculture Act 2020 to ensure “much-needed support” for egg producers.

The Government said the situation is being monitored but insisted the UK’s food supply chain is “resilient” and that no “significant impact” is expected overall.

A Defra spokesperson said: “We understand the difficulties that rising costs combined with the bird flu outbreak are causing for farmers and we are working with industry to monitor the egg market.

“The UK’s food supply chain is resilient – there are 38 million laying hens across the country and we are not expecting any significant impact to the overall supply.”

The NFU said a declaration under section 20 of the Agriculture Act “would enable Defra to use its statutory powers to provide much-needed support to egg producers whose livelihoods are under threat”.

There are a huge range of issues facing the poultry sector, in particular within the egg supply chain, which have built up over months and which we have been warning of for some time

The union’s president Minette Batters said it is “critical” that the Government acts now to give producers “the confidence they need”.

She said: “There are a huge range of issues facing the poultry sector, in particular within the egg supply chain, which have built up over months and which we have been warning of for some time. Energy price inflation and supply chain disruption have added to the worst outbreak in Avian Influenza yet. However, these pressures alone cannot explain empty shelves.

“The NFU raised concerns about the functionality of the supply chain with Defra a number of months ago in the hope of avoiding the situation we have now, with some retailers having to limit UK consumers’ access to eggs. This is surely a prima facie case of severe disturbance to an agricultural market.

“It is critical that Defra acts now to investigate the issues in the egg supply chain so that any declaration under section 20 can be made as soon as possible.

“Poultry and egg producers must have the confidence they need, working within a fair and transparent supply chain, with fair returns for farmers, so they can do what they do best; meet demand from shoppers for quality British eggs and poultry meat.”

The UK is facing its largest ever bout of bird flu.

This is compounding existing shortages caused by producers cutting back on output or leaving the industry due to increased costs, with Russia’s invasion of Ukraine driving up farmers’ energy bills along with the cost of chicken feed, hens and packaging.

Demand for eggs is also up as consumers seek out cheaper sources of protein to offset soaring food bills.