A trade agreement to import produce into the European Union is set to be conditional upon animal welfare requirements for the first time.

Eggs imported from Brazil, Argentina, Paraguay and Uruguay to member states will only be duty-free if the hens are kept in line with EU standards under the provisional terms of the new EU-Mercosur trade agreement.

Previous EU free trade deals have included aspirational provisions on animal welfare, such as the 2014 EU-Ukraine association agreement, but this is the first time the elimination of tariffs have been conditional upon particular standards being upheld.

Q&A What is the EU-Mercosur trade deal? Show Provisionally agreed in June 2019 after some 20 years of negotiating, the EU has signed a trade agreement with the Mercosur nations - Argentina, Brazil, Paraguay, and Uruguay. The agreement will cover a combined population of 780 million, making it one of the largest ever trading bloc arrangements by size. EU's exports to the Mercosur countries totalled €45bn in 2018. Goods travelling in the other direction amounted to €42.6bn in 2018. The EU is the biggest foreign investor in the region - €381bn in 2017. Trade in services between the two regions was valued at €34bn in 2017. Critics of the deal have said that it has taken too long to sign, and that with the climate emergency, a deal that will facilitate the easier shipping of animal products across hemispheres conflicts with the EU's stated aim to reduce greenhouse emissions. As a result of the deal, EU companies will save €4bn worth of duties per year. Since 2014, EU trade agreements with 15 countries have entered into force, notably with Canada and Japan.

Campaigning organisation Eurogroup for Animals welcomed the condition – which it hailed as “an important turning point in EU trade policy” – but criticised the absence of a similar prerequisite for meat and egg product imports, and called for the approach to be extended.

The RSPCA said the announcement that the agreement would be conditional on meeting EU animal welfare standards established “an important precedent” and was a highly significant move.

“It is the first time animal welfare standards have been incorporated into tariffs in an EU trade agreement, and something the RSPCA has been advocating for 15 years,” a spokesperson said.

“We urge the UK to do the same as it leaves the EU, by rolling over this particular trade agreement and including those welfare standard conditions in any future post-Brexit free trade agreements.”

The agreement was quietly made public in a meeting of the Committee on Agriculture and Rural Development at the European Parliament last Wednesday, after a leaked document seen by the Guardian suggested the EU had made the demand back in 2016 during the drawn-out negotiations with Mercosur.

“There is a cooperation provision in the agreement on animal welfare issues with the very clear objective to improve the level of animal welfare, particularly in the Mercosur countries, to bring them up to our world leading standards,” said John Clarke, director of international affairs at the European Commission’s directorate-general for agriculture and rural development.

“For the first time in any trade agreement, we have a condition attached to the export of eggs from Mercosur. They can only be exported at zero-duty if the Mercosur producers meet European standards for laying hens.”

Copa-Cogeca, a group that represents European farmers, called for greater work to be done to ensure states with bilateral trading agreements have reciprocal animal welfare standards.

“This is central for us, as currently animal welfare is not a universally accepted concept amongst our trading partners,” a spokesperson said. “Some of our trading partners have committed to align their animal welfare standards with the EU, but all too often they have failed to do so.”

Compliance with EU laws adds 16% to the cost price of an egg, according to the European Egg Processors Association. It said the condition would help make eggs from EU producers more competitive with foreign imports.

The British Egg Industry Council said that while the announcement represented “a step forward” it wanted to see the same animal welfare conditions apply to egg products and eggs used as ingredients in food exported to the UK.

European Commission sources downplayed the significance of the trade condition and said it would not have a major impact as shelled egg imports from Mercosur countries were limited.

Both sides are now preparing the final version of the trade agreement, the largest the EU has ever struck in terms of tariff reduction, before it is submitted to EU member states and the EU parliament for approval.

From 2012, farmers across the EU were no longer allowed to keep hens in barren battery cages, within which movement is extremely restricted. However, the cages were often replaced with more spacious versions and a large proportion of the EU’s 500 million hens remain caged for their entire lives.