The platform was unavailable for six days as it was moved to FNZ and when it came back online investment advisers found their clients were locked out of it.
Since then advisers have experienced a string of problems when using the tool, including delayed payments, inability to view client tax codes and its capital gains tax report providing incorrect information.
On Thursday, UK news publication FTAdviser reported that an adviser, who did not wish to be named, pulled all his clients from the platform as their investments have experienced severe disruption.
Another adviser said they had experienced problems with transacting fund switches and contributions being dumped then randomly allocated to funds.
An Aviva spokesperson admitted to International Adviser that customers who have been primarily affected are those who do business with them through financial advisers.
“Customers and advisers have experienced difficulties in the last few weeks as a result of changes to our technology, and we are sorry.
“The issues have only affected a small proportion of our savings and investments customers,” the spokesperson said.
Some customers had been affected by late or incorrect payments, however the spokesperson said, “the vast majority of these have now been resolved and paid”.
“We will ensure that no-one is disadvantaged financially by any issues that have arisen.”
Further, the spokesperson said Aviva is taking steps to deal with the high volume of calls its call centre is receiving.
“We have re-allocated resource in the business to deal with the unprecedented levels of calls, and as a result call waiting times have now reduced considerably.”
The spokesperson said Aviva would continue to work through resolving the issues that have caused advisers and customers difficulty.
“We appreciate the impact this is having on advisers and their clients and we are working hard to resolve remaining issues as quickly as possible,” the spokesperson said.
International Adviser approached FNZ for comment but did not receive a response at the time of publication.