A staff survey conducted in June last year painted a damning picture with a mere 19 per cent of staff polled believing senior management at the Fos provided a clear sense of direction and 21 per cent thinking their top bosses were open to feedback.
Fos changed from a structure where adjudicators specialised in a product area and were assigned complaints in that area to one where the person who first receives the complaint will consider the complaint.
On 15 January, speaking before the Treasury select committee, chief executive Caroline Wayman (pictured) acknowledged that staff had been unhappy about the changes and pledged to boost staff morale.
She said: "We are absolutely not removing specialisms. What we are trying not to do is to have queues at the front end, which means we need to be able to be flexible enough to be able to respond to whatever people bring to us in that week."
But Ms Field said the issues identified by the investigation were a cause of concern for the industry and needed to be dealt with seriously.
She called for a review of the Fos training regime to ensure staff have sufficient knowledge when dealing with complex pension, advice and investment claims.
Ms Field said: “An evaluation of internal culture is essential to deal with issues identified such as the obvious lack of necessary training and the setting of unachievable targets, which seriously impacts the decision-making process.”
The FCA is currently consulting on giving small businesses access to the Fos, which could increase the service's caseload by about 1,500 cases a year.
A Fos spokesperson said this would be "well within the caseload variances" the service already plans for but it was "considering whether we need any additional specialist skills to look at the potential new cases".
Ms Field said: “Any planned extension to the remit of FOS should be suspended until we can be assured that staff have the necessary knowledge to deal with the subject matter competently to achieve just decisions.
“These fundamentals need to be resolved to ensure that clients and firms can access a sustainable, impartial, evidence based dispute resolution model.”
Dave Penny, managing director at Invest Southwest, said he was "horrified" by the news.
He said: "We are all dealing with life changing issues both as financial institutions and as ultimate arbiters of the complaints process.
"Accuracy is essential and in order to achieve this, expertise is an absolute prerequisite. It is hard to believe that the Fos believes all staff have the ability to judge all cases and to my mind is a betrayal of trust in favour of attempting to meet arbitrary targets."
He said the Fos had to ensure it trained staff properly and let them specialise. It should also take the flack for delays.