WASHINGTON (Reuters) - A U.S. banking regulator is considering whether to harden sanctions against lenders that abuse their clients or violate banking laws, according to a draft plan, seen by Reuters, that was drawn up in the wake of a scandal at Wells Fargo.

Wells Fargo in September agreed to pay $190 million to settle charges that bank employees opened as many as 2 million accounts without customers’ knowledge. The fraud went on for at least five years, said the San Francisco-based bank that fired 5,300 employees involved.

The Office of the Comptroller of the Currency - the chief regulator for national banks - waived its right to curb executive payouts, screen new leadership and other controls at Wells Fargo following the scandal.

But, according to a memo outlining the new policy, the agency expects tougher scrutiny on when to issue such exemptions in the future and senior officials should be involved in any decision.

The memo said that officials with the agency should not waive sanctions “until appropriate OCC personnel have conducted a case-by-case evaluation about whether granting such relief is warranted.”

In recent years, other national lenders such as Bank of America and Citibank have been granted exemptions similar to those Wells Fargo received.

Until a thorough, written policy is developed by the OCC, officials should refrain from granting relief from the toughest sanctions permitted, according to the memo dated November 18.

An OCC spokesperson was not immediately available for comment.

On Friday, the OCC voided the exemptions that it had originally granted Wells Fargo in a September settlement.