Health advocates warn that many Australian children are eating too much salt in their diets.
Victoria Health and the Heart Foundation have launched the Unpack the Salt campaign, to educate caregivers on the high sodium content of popular lunchbox food items.
Heart Foundation Victoria's CEO Kellie-ann Jolly told SBS News the campaign would help families make better choices.
A study of 16 thousand Australians has found many are eating in excess of the maximum daily salt recommendation. Source: Press Association
Ms Jolly said sandwiches were a major culprit, with spreads and fillings contributing to high sodium levels.
Dietitians said even the bread commonly sold in supermarkets was a key contributor.
"What we're hoping is that parents will just be aware of the fact that any of the fillings that they might be putting in sandwiches are actually containing too much salt," Ms Jolly said.
"What we'd like to do is just think about that, try and go for a healthier option, read the labels on your food labels just to check they are lower salt options, and just to be aware of that when you're making school lunches."
The recommended daily salt allowance for children aged four to eight is 3.5 grams, while the highest recommend intake is five grams - a teaspoon of salt - for children aged nine to 13.
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However, many popular snacks are so high in salt that many children have met their daily requirements by the time they've had breakfast.
"We see that children are consuming too much salt as children and what that can do is actually lead to organ damage in adulthood and even can contribute to high blood pressure as we get older," Ms Jolly said.
"So it is really important that we try and keep our salt intake within the daily allowance, so we aren't putting children at risk as they get older."
Various stakeholders, including the Heart Foundation and George Insitute of Global Health, are lobbying the federal government to set salt targets for food categories and to review major brands' compliance with the targets.
Professor Bruce Neal from the Food policy division of the George Institute of Global Health led the research in a new study of salt consumption by Australians.
Mr Neal told ABC radio he believed the responsibility should rest with regulators, rather than households.
"In countries like Australia where we eat a lot of processed food and a lot of restaurant food, exactly as you say, the salt is hidden. It's added during food manufacturing and processing," he said.
"As a consequence, unless you read labels really carefully, which most people don't, then it's really not possible to understand just how much salt you're eating. The salt that you add at the time of cooking or at the table is usually on 10 or 15 per cent of the salt you eat in the day."
File Source: Press Association
Ms Jolly recommended some quick and easy options for busy parents.
"We understand that you need to make these quick and easy decisions when you're trying to make school lunches in the morning," she said.
"So things such as egg and lettuce, roast chicken and avocado or even cheese and carrot. They all contain far less salt than your typical ham and cheese or Vegemite cheese sandwiches. So we're not saying give up sandwiches altogether - just be aware of the type of fillings you're putting in your children's school lunch boxes."
The NSW Government has unveiled another health initiative for teenagers, to manage and prevent obesity.
Students in years seven to nine across 76 state and Catholic schools will be part of a trial, which will see them undergo routine physical activity and testing and regular weigh-ins, with scales in classrooms.
The program also looked into whether splitting the students by gender will make them less inhibited, and therefore less likely to skip group exercise due to being self-conscious.
