Forcing food manufacturers to cut salt levels in processed food could help cut heart disease rates, claim Australian researchers.
A theoretical study suggests mandatory salt limits could help reduce heart disease rates by 18% - far more than by using existing voluntary measures.
High-salt diets are linked to high blood pressure, which can lead to heart attacks or strokes.
Adults are advised to consume a maximum of 6g of salt a day - about a teaspoon.
The study looked at the effectiveness of different strategies around the world for reducing salt in processed foods.
Many countries, including Finland, the US, the UK, Canada, France, Australia and New Zealand, have adopted salt reduction programmes based on food labelling and voluntary cuts.
Australia uses a "Tick" programme, where food manufacturers can use a health promotion logo on packaging if they volunteer to cut salt content.
The team calculated that voluntary use of the logo could reduce heart disease rates in Australia by almost 1% - more than twice that of dietary advice alone.
But if all manufacturers were made to use the logo, the health benefits could be 20 times greater, they predict.
"If corporate responsibility fails, maybe there is an ethical justification for government to step in and legislate," the authors, led by Linda Cobiac, of the University of Queensland, write in the journal Heart.
A UK heart charity said voluntary measures placed on food companies in the UK had made a difference but more could be done.
Victoria Taylor, senior heart health dietician at the British Heart Foundation, said: "We're making progress without the need for compulsory limits and as a result we've seen a reduction in salt intake.
"But as three quarters of the salt we eat is already in the food we buy, we need to build on this work and watch carefully to make sure the food industry doesn't slip back into old habits."
Katharine Jenner of Consensus Action on Salt and Health (CASH) said the UK had pioneered a voluntary approach where all food sectors reduce the amount of salt they put in food.
"This cost-effective approach has been very successful and has already led to population average salt intakes falling by 10%," she said.