Curry lovers are being warned about the high levels of salt in the dish.
Research by Consensus Action on Salt and Health (Cash) showed the salt content in some dishes was more than the daily recommended limit.
The campaign group warned with side-dishes, such as naan bread and chutney, salt levels could be even higher - but some healthier options were found too.
Nearly 800 products in supermarkets, independent shops and takeaways were analysed during the research.
The recommended maximum intake of salt is 6g a day.
But the researchers found one chicken tikka masala takeaway had 6.8g per portion, while curries on sale at Iceland also had more than the daily limit.
'Worrying'
Even rice was found to be fairly high with one brand containing 1.4g per portion and naan bread having 3.2g.
Katharine Jenner, from Cash, said: "A regular curry night is becoming a British institution, making these high salt levels extremely worrying.
"This survey shows salt can be hidden behind all the spices and chilli in your curry, even in side dishes and sauces.
"Add to this the lack of clear labelling on packaging in takeaway restaurants and it makes it very hard for consumers to choose a healthy option."
But Cash said if people shopped around they could find lower salt options.
Both the Co-operative's Healthy Living Rogan Josh and Weightwatcher's Korma had just 0.5g per portion.
A spokesman for Iceland said it had been working with suppliers to reduce salt levels.
"We have achieved reduction in salt levels over the last number of years in most product areas bringing the majority of them into line with the Food Standards Agency targets."
Julian Hunt, of the Food and Drink Federation, added: "UK food manufacturers are leading the world on changing the recipes of their products - including cooking sauces and ready meals - to contain less salt."
Research by Consensus Action on Salt and Health (Cash) showed the salt content in some dishes was more than the daily recommended limit.
The campaign group warned with side-dishes, such as naan bread and chutney, salt levels could be even higher - but some healthier options were found too.
Nearly 800 products in supermarkets, independent shops and takeaways were analysed during the research.
The recommended maximum intake of salt is 6g a day.
But the researchers found one chicken tikka masala takeaway had 6.8g per portion, while curries on sale at Iceland also had more than the daily limit.
'Worrying'
Even rice was found to be fairly high with one brand containing 1.4g per portion and naan bread having 3.2g.
Katharine Jenner, from Cash, said: "A regular curry night is becoming a British institution, making these high salt levels extremely worrying.
"This survey shows salt can be hidden behind all the spices and chilli in your curry, even in side dishes and sauces.
"Add to this the lack of clear labelling on packaging in takeaway restaurants and it makes it very hard for consumers to choose a healthy option."
But Cash said if people shopped around they could find lower salt options.
Both the Co-operative's Healthy Living Rogan Josh and Weightwatcher's Korma had just 0.5g per portion.
A spokesman for Iceland said it had been working with suppliers to reduce salt levels.
"We have achieved reduction in salt levels over the last number of years in most product areas bringing the majority of them into line with the Food Standards Agency targets."
Julian Hunt, of the Food and Drink Federation, added: "UK food manufacturers are leading the world on changing the recipes of their products - including cooking sauces and ready meals - to contain less salt."
