An easy-to-understand, flat-tax savings scheme promised by Minister for Finance Simon Harris will not be ready to go live next year unless he publishes an outline of how it will work very shortly, an industry group has warned.Almost six in 10 adults said they would be interested in investing through the new regime, which aims to unlock some of the €170 billion attracting little return in bank savings, according to a survey by investing platform IG.More than half of those – 35 per cent of all respondents – would be first-time investors, the IG survey found, with only one in three Irish adults currently investing outside their own pension scheme.However, IG says time is running short if Harris is to launch the new savings scheme next year, as planned. “There is now an urgent need for clarity on the final rules if firms have any realistic prospect of supporting a launch in 2027,” said Michael Healy, UK & Ireland managing director at IG.Back in February, when Harris announced his plan to bring in personal investment accounts, he said he would publish a framework document for his proposed incentive scheme “in the coming weeks”.Since then, the only substantive update has been to clarify at the end of March that the new regime would carry an annual flat tax rate on assets above a tax-free limit with account providers managing all tax issues for investors in a one-stop shop arrangement.That pointed to the Government favouring the Swedish ISK model, but it has since seemed to be moving closer to UK ISA-style accounts over fears that the Swedish model would disproportionately favour those who were already wealthy. However, there has been no clarity.ISAs allow people to invest up to £20,000 (almost €23,000) a year from their taxed income in funds where the any dividend income, capital gains or interest is free of tax.Swedish ISKs impose no upper limit on how much can be invested, but applies a nominal rate of tax annually across all the funds in an account above a threshold of 300,000 Swedish kronor (€27,400).When asked in its survey, IG says Britain’s ISA model proved over twice as popular with likely savers than the Swedish version.IG says the Government now needs to prioritise simplicity in the scheme design to encourage wide buy-in from both consumers and providers.“Ireland has a major opportunity to create a simple and competitive investment framework that helps more people build long-term wealth through investing,” IG’s Healy said. “Simplicity will be critical to driving participation and ensuring strong competition across the market.”Stripping out deposits held in longer-term accounts, savings of sole traders and certain small businesses that are categorised by the Central Bank as household deposits, and an estimated 40 per cent of balances held by customers over 65 years of age, Banking and Payments Federation Ireland found that between €20 billion and €30 billion could potentially be put to work in tax-efficient personal investment accounts. It suggested as much as €7 billion in retail investor funds could move to the new scheme in its first year.