The initiative has been devised under the Milk Development Council's (MDC) School Milk Project. And the MDC is working with the Health Education Trust to engage schools, dairy companies, authorities and vending machine suppliers.
Diane Cannon, manager of the School Milk Project, told DairyReporter.com that the first milk vending schemes were planned to begin in Wales around February next year.
She said the MDC had the backing of the Welsh Assembly and the UK Food Standards Agency as part of government plans to make sure that the only drinks available in secondary school vending machines will be milk, water and fruit juice.
The move offers significant opportunities for UK dairy firms to get more products into schools amid concerns over children's junk food habits.
And there may be scope to attract a wider range of consumers due to government plans to open up schools out-of-hours in the style of community centres.
The School Milk Project, partly funded by the European Union, has already begun putting more milk into schools, with 800 new schemes set up this year and 700 last year.
"We need to make companies realise the potential that is in front of them," said Cannon, adding that the machines could sell other dairy products like drinking yoghurts as well as milk.
She said it was important to consider children's needs. "They've got to be thinking about one-shot drinks that children can just pick up and run with. It's all about what choices are available."
The MDC and Health Education Trust have been co-ordinating negotiations between school authorities, companies and vending machine suppliers on how any contract arrangements might work.
"They won't just be milk machines. For a vending machine to work you have to have a choice of products in there," said Cannon.
One potential sticking point for schools is the money they are able to make from healthy vending schemes.
"We have heard from schools that they have the potential to have a regular stream of revenue from soft drink companies if they keep their products in schools," Cannon said.
"We are looking at the best options for the schools in terms of logistics and practicability. Schools have to be able to recoup something from the machines."
She said a trial of a milk vending-style scheme was conducted from 2002 to 2004. "All the schools that took part saw increased profits with healthy choices in the machines, and milk actually came out as the top seller. Schools realise there is huge potential there.
"We are concerned with the health benefits for the children. We want to look at re-educating children, schools and authorities on why they should be making these choices."
Cannon said there was not yet a final number for participants in the new vending initiative, but it was possible more than 100 schools could be involved before the end of 2006.
UK milk processor First Milk has already worked with the MDC to launch Milk Bars in some secondary schools.