A survey carried out for communications regulator ComReg has estimated that 24% of homes now use mobile phones only, with no fixed-line subscriptions.
The survey of 1,000 people, by consultants Amarach, found that this trend was mainly among younger age groups and lower income groups.
It also found that almost 40% of consumers were aware of third generation mobile services, with 7% suggesting that they were likely to sign up in the next three months. Those aged 15-24 were most likely to subscribe.
69% of households now have some form of pay-TV service, with 32% subscribed to digital television.