Religious leaders in the UK have called for all meat sold in the country to be labelled with slaughter details.
The call for comprehensive labelling came after reports that people eating at Pizza Express and other restaurants were consuming halal-slaughtered chicken without their knowledge.
The BBC reported that the news prompted the hashtag #halal and then the backlash hashtag #halalhysteria to trend on Twitter in the UK.
Representatives of both Jewish and Muslim groups said in a letter to the UK-based Daily Telegraph newspaper on Thursday that consumers should know how animals were killed before they buy meats.
"Comprehensive labelling should be supported by faith communities and animal welfare groups alike," said the letter signed by Henry Grunwald, chairman of Shechita UK, the body that represents the Jewish method of religious slaughter, and Dr Shuja Shafi, deputy secretary-general of the Muslim Council of Britain.
Currently there is no labelling requirement in terms of halal.
The letter also said that food labels should specify whether or not an animal has been stunned prior to slaughter "and whether it has endured repeat stuns if the first attempt was ineffective".
"They should also be told the method of slaughter: captive bolt shooting, gassing, electrocution, drowning, trapping, clubbing or any of the other approved methods," the letter added.
More than 70 percent of New Zealand lamb sold in the UK now comes from halal slaughterhouses, although there is currently no requirement for slaughter information to be stated on packaging.
Halal methods are used to ensure that meat can be sold in both Muslim and non-Muslim countries.
"Currently there is no labelling requirement in terms of halal," Craig Finch, the UK and Europe regional manager for Beef and Lamb New Zealand, told the AFP news agency. "It's based on commercial and logistical factors. We take a consistent approach that meets regulations across the board in our different markets around the world."
In response to whether or not he thought labelling should be considered in the UK, Finch said that it was up to regulators in different markets to decide.
"It really becomes a regulatory issue," he said. "But that information about slaughter methods is already clear on our website."
Finch added that all of the lamb exported to the UK was from sheep that had been "pre-stunned" and were unconscious before slaughter, in accordance with New Zealand law.