Although the discounters' growth had slowed dramatically over the past year, they were still growing at a faster rate than the rest of the grocery market, revealed Mike Watkins, senior manager for retailer services at Nielsen.
Aldi, Iceland, Lidl and Netto currently had a combined market share of 7.9% but had the potential to grow this to a share of 10%, he said.
"The discounter boom is not over it has only just begun," he claimed. "The discounters are here to stay. One third of shoppers will still look for cheaper brands after the recession, according to our research. The discounters have changed the retail map and it's more than just a day in the sun. Build stores and the shoppers will come."
However, he admitted life had become tougher for the discounters because the supermarkets had moved into their territory by offering more promotions, £1 deals and discounter ranges.
As a result, the discounters' growth had fallen from 31% at its peak at Christmas last year to 7% in October only just above the big four's growth of 5.5%, he said.
Meanwhile, Iceland boss Malcolm Walker, who headlined the event, played down Iceland's slowdown in sales growth, which was down to 5.4% in the 12 weeks to 4 October, from 14.2% in the 12 weeks to 27 December.
"Our growth couldn't continue at that rate like-for-likes will flatten off," he said, adding that Iceland would open 70 stores in 2009 and another 20 next year to help maintain its momentum.
Walker was among a number of retailers at the conference who called on suppliers to help discounters compete with the big four by providing new pack sizes designed exclusively for the channel as well as sharper prices.
"We need suppliers to help us to have a point of difference over the supermarkets," he said.