The 100% mortgage was supposed to fit the bill but it does not look so smart now that interest rates continue to rise and storm clouds gather over the future direction for house prices.

Despite the flood of easy credit, there is no substitute for putting some of your own money on the table. At the very least it gives you some protection if prices start to slide, providing a buffer against negative equity, where you end up with a house that's worth less than the mortgage.

The big challenge in getting a deposit together is that you are chasing a moving target. Save the money in the bank or credit union and you will earn a miserable rate of interest that in no way keeps pace with galloping inflation in the housing market.

Take a chance by investing your deposit in stocks and shares and you risk losing a big chunk in the type of downward spiral engulfing stock markets at the moment.

But a solution of sorts could be around the corner.

Basking in the new lease of life provided by its Danish owners, National Irish Bank is preparing to launch something completely different: a structured note tracking the performance of the residential property market.

At first glance, it looks perfect for the struggling first-time buyer. Because performance is tied to the property market, your savings should rise and fall . . . or more likely rise and rise . . . exactly in line with house prices, allowing you break out of the vicious cycle whereby the longer you save, the less property your money will buy.

It will be a three-year investment, giving you some breathing space to keep on saving without locking away your existing nest egg for too long. The product will have a familiar ring, similar in nature to the tracker bonds that Irish savers have bought by the bucketful in recent years.

They tracked the stock market; NIB plans to track the property market.

The big attraction for many is that the investment will have a safety net so that, if the doomsayers are finally proven right and the property market does crash, you will at least get back your original capital at the end of the three years.

Another selling point is that you will be able to take back some of your savings before maturity, although it might not be wise to crack open your piggy bank if you are really serious about buying a place of your own.

But no investment is a silver bullet and NIB's structured note has certain flaws that should cause property hopefuls to think twice.

The biggest drawback is that it will track the Halifax index of British house prices, which is hardly a suitable benchmark for somebody planning to buy in Ireland.

According to the homegrown Permanent TSB index, house prices in Ireland have tripled in eight years, rising from an average 98,000 in March 1998 to 287,700 by March of this year. In Britain, growth has been more modest, with the price of the average home rising from £70,500 ( 103,391) to £173,000 ( 253,710), over the same period.

If your savings had tracked the Halifax index since 1998, you would have made a return of 150%. But you would have needed 200% growth just to stand still in the Irish property market.

With different demographics, interest rates and very different planning laws, the UK makes a very poor barometer of the property market in Ireland.

The word from NIB is that an investment tracking the Permanent TSB index is entirely possible; just don't hold your breath.

Even if it were available, a catch-all index would be of limited value. House prices in Dublin are still growing faster than in other parts of the country, so that hitching your savings to a national index would leave you shortchanged if your plan was to buy in the capital.

Another flaw is that, to pay for the capital guarantee at maturity, NIB will not give you the full growth of the underlying index. This is a trade off with which anyone who ever put their money in a tracker bond will be familiar: the stock market grows by 90% over the investment term but you only get 70% because, if the markets had moved in the opposite direction, your money would have been protected.

NIB's plans for a property-based tracker is a definite move in the right direction. But it needs more fine tuning.