Families are expected to hack away at 100,000 pumpkins this year, devour lollies by the bucketful and dress their children with fangs, spooky ghost sheets or witches hats as the ghoulish festival of Halloween becomes increasingly popular.

The supermarket chains have spent millions promoting Halloween, which will be celebrated on October 31, with sales of easier-to-carve Jack O'Lantern pumpkins already up by 30 per cent.

Confectionary companies have created Halloween chocolates for the Australian market to feed the growing popularity of the essentially American holiday. Coles has reported that chocolate sales on the eve of Halloween day can be three times that of a normal trading day.

''People will start shopping from this week on, but really October 30 is our biggest trading day around Halloween,'' Coles' general manager of merchandise Chris Garlick said.

''We are seeing a gradual increase in how many customers get involved, and it's probably a generational thing, too, where this generation with young kids are getting more and more into it.''

Not to be outdone, Woolworths is selling a range of pumpkin-flavoured beer and is using social media to spread the word, with online tools such as instructions on how to carve a pumpkin, and offering customers a stencil to download. The fresh produce wholesaler Moraitis is the only grower of Halloween pumpkins in Australia and is expecting to sell about 100,000 this season to the leading supermarket chains as well as independent grocers. Moraitis has increased its Jack O'Lantern pumpkin planting by 10 per cent a year to meet demand.

Halloween is also proving to be a young person's event. New data from McCrindle Research shows that Generation Y (those aged 18 to 31) were far more likely to have celebrated Halloween than Generation X (aged 32 to 46) and baby boomers ( aged 46 to 65). The social researcher Mark McCrindle said that, when asked if they had ever celebrated Halloween, 53 per cent of Gen Yers had, compared with 45 per cent of Gen Xers and 40 per cent of baby boomers. More than 50 per cent of parents with primary school age children planned to embrace Halloween, he said. ''It is certainly growing,'' the chief executive of the Australian National Retailers Association, Margy Osmond, said. ''It's another opportunity to have a bit of a celebration with the family, so there is quite a bit of Halloween-specific products creeping into the stores … and we do know [that] it's getting more popular.''

Retailers say Halloween is still small in terms of expenditure compared to Mother's and Father's Day, or AFL grand final week, but it is growing by up to 15 per cent a year, led by money spent on chocolates and costumes that typically sell for less than $15. Toilet paper also sells well, as children like to wrap themselves up to look like mummies.