NAB could face legal action over more than 100 breaches of corporate law in actions that flew in the face of its best interest obligations to clients, the financial services royal commission has heard.

Submissions to the commission showed NAB could be liable for criminal or civil penalties over the breaches and another four potential cases of misleading and deceptive conduct.

Letters from ASIC released to the commission identified 110 breaches of the ASIC act that demand any breaches of corporate rules be reported to the regulator within 10 days.

NAB in response to ASIC said it had breached the reporting rule 84 times. ASIC has still not decided whether to take further action against NAB on those issues.

On Wednesday evening NAB counsel Neil Young QC tried to get Nicole Smith, former chair of NAB superannuation trustee Nulis excused from further testimony and to protect a number of documents from disclosure by the commission.

That request was rejected and the documents concerned lead to Thursday’s admissions.

NAB executive and former chair of its superannuation trustee, Nicole Smith, finished nearly three gruelling days in the witness box by denying four propositions put to her by counsel assisting Michael Hodge QC that came from his assessment of her evidence.

Ms Smith denied the bank had not acted in the best interests of clients in retaining grandfathered commissions after commissions became illegal on new superannuation investments and in being slow in moving funds from high cost accounts to low fee MySuper accounts.

When the MySuper accounts were formed Mr Hodge said members’ interests were not sufficiently prioritised in monitoring or running them. NAB super trustees also sat silent “persistently, over several years,” while NAB management negotiated with ASIC to try to retain fees-for-no-service and “a failure to prioritise the interests of the members over the interests of the NAB Group?” Mr Hodge said.

Ms Smith replied “no” to all propositions.

However, the commission heard that while Ms Smith was chair of NAB trustee organisation Nulis she signed letters to regulators putting forward the view that some of NAB’s fees on superannuation accounts were justifiable because they paid for potential services members could receive.

“And nevertheless, you signed a letter saying it was a fee for access to service?” she was asked.

“Yes,” Ms Smith replied.

“And …?”

“And I had also signed off multiple other pieces of correspondence that said words like ‘it is a fee for access to and the provision of ongoing following service’.”

Ms Smith disagreed that the fees were actually charged for advice, not the potential of getting advice.

One document released at the commission showed that NAB only planned to remediate all customers who had signed up in accounts from 2015 and were charged fees-for-no-service. For older customers an opt-in arrangement was put forward which would have resulted in far fewer customers being paid out.

Ms Smith said she did not agree with that approach and at times she said she had not known management were trying to negotiate that outcome with ASIC despite being chair of the trustee with responsibility for the funds concerned.

In July this year NAB agreed to remediate 3005,000 customers about $87 million for fees-for-no-service. That followed a similar payment of $34 million the previous year.

A note from ASIC produced in the commission described commission-based remuneration structures as being “opaque, lack any corresponding customer service obligations and are not generally understood by customers”.

Ms Smith said she agreed with that characterisation.