The Government says that any extension to the Retail Deposit Guarantee Scheme will come at a greater cost to financial institutions.
The scheme was introduced in October 2008 to give assurance to depositors during the recession, when some global markets were facing a financial meltdown.
It was originally set up for two years, but the Government has announced it will extend it until the end of 2011.
Finance Minister Bill English says the premiums to join the current scheme do not come close to covering the costs the Government has paid out to investors.
Mr English says entry to the next guarantee scheme will be much more expensive, in an attempt to retrieve some of the real costs of the guarantee.