The Post Office has admitted IT training and support failings may have resulted in some users of its Horizon system being wrong accused of false accounting.
The Horizon computer system, which is used to monitor transactions within the Post Office branch network, has been at the centre of a bitter dispute between the company and its sub-postmasters for some time now.
More than 100 have filed complaints about the system after being accused of falsifying accounts. In some cases, sub-postmasters have been prosecuted or ordered to repay money after the system flagged up non-existent shortfalls.
Horizon is reportedly used by 68,000 people working across 11,500 Post Office branches and handles around six million transactions every day.
The Post Office called in forensic accounting firm Second Sight last year to investigate the claims, and has confirmed in a statement its review did not uncover any "system-wide" problems with Horizon.
However, it did throw up two instances in 2011 and 2012 when system defects resulted in shortfalls of up to 9,000 at 76 branches.
Even so, the organisation said Second Sight's findings have cast doubts on the training and support the Post Office provides sub-postmasters that use Horizon.
"The interim review makes clear that the Horizon computer system and its support processes function effectively across our network...[and] underlines our cause for confidence in the overall system," said Post Office CEO Paula Vennells, in a statement.
"It does, however, raise questions about the training and support we have offered to some sub-postmasters and we are determined to address these issues."
In response to Second Sight's findings, the Post Office said it plans to rollout three new initiatives to address the concerns of sub-postmasters more effectively in future.
These include the creation of a Branch User Forum, where sub-postmasters can raise issues about business processes, and the development of a working party to review the complaints made about Horizon.
A review will also be undertaken and chaired by an independent figure to help make it easier to work through disputes of this nature in the future.
"The people who work in the post office network in communities across the country are the lifeblood of our business and we take our responsibilities to them very seriously," Vennells continued.
"In many of these cases I am confident that steps have already been taken which have improved support and training but we are always open to feedback and insights from sub-postmasters.
"So we will make further improvements in this area and take better account of individual requirements and circumstances going forward," it concluded.
