According to new research by AIB, there has been a big shift in people's reactions to their SSIAs once the accounts actually mature. The result is that people who expected to invest the money long term are opting instead for instant-access deposits.

Those who thought they would use the SSIAs to pay down their mortgages have ended up clearing credit card debts.

And fewer people than expected are splashing out on holidays and new cars.

The research, undertaken by market research firm Red C, also found that it takes people several months after their SSIAs mature to decide what to do next.

The results reflect mounting worries about the economic outlook said Hugh O'Keeffe, head of savings and investments at AIB.

"There's a fair degree of caution out there and the survey results are backed up by what we're seeing on the ground, " he said.

"It mat be a reaction to the four interest rate increases we've seen since December with another two on the way.

That's a fairly significant jump in mortgage costs."

A deposit war between the banks, with many paying savers a return in excess of the base rate of interest, may be contributing to the high proportion of SSIA savers leaving their money in instant-access accounts, O'Keeffe said.

The survey results may be skewed by the fact that people whose SSIAs have already matured are believed to be more financially savvy, getting into the scheme earlier than most other savers.

While only one-third of SSIAs will mature this year, O'Keeffe said they account for 55% of the 16bn invested in the scheme.

"I have the sense that the pattern will be different next year, " he said.

"Most of the people who took out equity-based SSIAs did so in the early days of the scheme. They were sold as a long-term game plan and, even though the SSIAs are now maturing, these people are inclined to stay put."