National Savings and Investments will release new issues of guaranteed growth bonds and guaranteed income bonds with revised terms and conditions.
The one-year and three-year guaranteed growth bonds and guaranteed income bonds, available from May 1, will offer customers a 30-day cooling off period.
Previously, customers who withdrew their finds early would have been subject to a 90-day interest penalty on the amount cashed in.
The interest rates remain unchanged, so the one and three year guaranteed growth bonds would pay 1.5 per cent gross/AER and 1.95 per cent gross/AER, respectively.
Meanwhile, the one and three year guaranteed income bonds will offer rates of 1.45 per cent gross/1.46 per cent AER and 1.9per cent gross/1.92 per cent AER, respectively.
Existing holdings will be unchanged until they mature and customers do not need to take action now.
NS&I will write to all holders of guaranteed growth bonds and guaranteed income bonds at least 30 days before their bonds reach the end of their term.
Ian Ackerley, NS&I’s chief executive, said: "NS&I is making this change to follow industry standards, however we recognise that committing to a fixed term of investment is an important decision, which is why we have introduced a 30-day cooling off period for customers investing in a fixed term.
"If customers think they may need access to their money, NS&I offers a range of easy-access products which are designed to offer this flexibility."
Darius McDermott, managing director at Chelsea Financial Services, said: "This appears a good move for consumers as it allows them to cancel within the cooling off period. This gives them a little extra flexibility as their circumstances may change."
