Supermarket giant Sainsbury's is to roll out "eco-friendly" milk bags and jugs across its entire product range in a multi-million pound move to reduce the carbon footprint of milk consumption.

In partnership with supplier Dairy Crest, Sainsbury's is putting its full marketing weight behind the product, confident that reluctant consumers now understand how to use it after a series of technical modifications and an education programme. The push comes despite the failure of a similar product by rival supermarket Waitrose, which launched in 2007 and was quietly shelved this April.

Sainsbury's will today stock whole-milk bags following healthy sales of a trial of semi-skimmed milk bags, to be followed by skimmed and 1% fat milk bags next year. It says customers have bought twice as many as originally predicted – currently 120,000 semi-skimmed milk bags per week or one in every 10 two-pint semi-skimmed units sold. Sainsbury's expects the total number of bags to double following the expansion of the range.

The new product typically contains 75% less plastic than the bottles in which at least two-thirds of the 180m pints of milk consumed by Britons every week is sold. Less energy is used in making them and they take up far less space when disposed of. But many consumers have found them difficult to use, reporting leaks and spills. When Waitrose withdrew the product earlier this year it cited "poor sales". Tesco revealed today that it is to launch trials of Dairy Crest Country Life milk bags in 10 stores.

Sainsbury's claims modifications to an earlier prototype jug and bag launched in 2008 have been made to make the product easier to use, and in February this year the new format was rolled out across all stores.

Emma Metcalf King, Sainsbury's senior dairy buyer, said: "This is the biggest change to occur to the nation's shopping habits for at least a decade."

Customers switching to bags could save up to 1,400,000kg of packaging every year, Sainsbury's said. To meet customer demand for milk bags, Sainsbury's and its supplier Dairy Crest have invested more than £2.2m in a new processing plant at its site in Gloucestershire. The expansion has created 20 new jobs.

As well as using less packaging, the product is also cheaper. Compared with an equivalent two pint plastic bottle, milk in a bag saves Sainsbury's customers at least 6p.

Bagged milk has been much more successful in other countries, with the jug and bag the overwhelming choice for shoppers in Canada.