The Commonwealth Bank legal team did not present documents to the financial services royal commission until after a case had been dealt with, raising the ire of Commissioner Kenneth Hayne.

An angry Commissioner Hayne has demanded the bank submit a written explanation of its actions by Tuesday night.

The nine documents related to CBA’s agricultural lending. One included crucial details of a miscreant banker who gave loans based on false valuations that led to a Queensland family having to sell their farm.

CBA’s counsel said the bank had “discovered” the documents on Thursday night while legal staff searched for the performance review of the manager – who the commission heard had inflated property valuations to meet lending targets and earn bonuses.

The documents showed the banker, whose name was withheld from publication for legal reasons, was guilty of worse misconduct than was disclosed to the commission on Thursday.

The undisclosed behaviour included going into the bank’s IT system to reset red flags on accounts back to zero – thus reducing the effectiveness of systems to identify when accounts were running into trouble and making his lending record look better. As a reward for that record, he won the bank’s rural and regional championship in 2011 and received a trip to Hayman Island.

Commissioner Kenneth Hayne has demanded an explanation from CBA. Photo: AAP

After the manager left the bank, his employer got access to his mobile phone. The records revealed a conflict of interest involving one of his relatives, who owned cattle grazed on a farm belonging to one of his customers.

A CBA file note characterised that as “potential conflict of interest!”.

CBA counsel Charles Scerri QC told the commission early on Friday that lawyers had learned of the documents about 10pm on Thursday. Commissioner Hayne became agitated, wanting to know exactly when the lawyers had received the documents.

After a short recess to allow the new documents to be redacted, it emerged that CBA’s legal team had actually held them for a month but had not dealt with them until Thursday night.

“I will consider what course is to be taken in relation to these matters,” Commissioner Hayne said.

The commission heard that in the case of the Ruddy family, who were forced to sell a property after the miscreant banker gave them a loan based on false valuations, CBA had eventually written off $600,000.

The commission also heard that Marg and Mel Ruddy’s son, who had acted as guarantor for part of the loan on one of their two properties, was given wrong information about his exposure.

He was told he would be guarantor for 25 per cent of the loan on one property. In paperwork he eventually signed, his exposure was actually spread across loans and on two properties.

By 2013, CBA became concerned that its lending to famers was becoming politically sensitive and felt care was needed in mediation negotiations.

“Our brand could be at risk,” an internal document submitted to the concession read. It is “therefore incumbent on the bank to handle such matters with integrity and compassion – which does not mean we given them more money.”