The Federal Court on Friday ordered the big four bank to pay the combined penalty after ASIC brought six civil proceedings against it in November last year.
ASIC deputy chair Sarah Court said more than 70,000 customers had been affected by the company either incorrectly charging them or providing the wrong information over a 13-year period.
"The breaches demonstrate a profound failure by Westpac over many years and across many areas of its business to implement appropriate systems and processes to ensure its customers were treated fairly," Ms Court said.
Westpac failed to prioritise and fund systems upgrades needed to meet financial services obligations, she said.
Westpac co-operated with ASIC and admitted the allegations in each of the proceedings. The bank will also pay back customers more than $80 million.
"Westpac again apologises to all affected customers," a company spokeswoman said in a statement.
A BREAKDOWN OF THE $113 MILLION WESTPAC FINE:
* $40 million for charging 11,800 deceased customers nearly $10.9 million worth of financial advice, with no service provided, over a 10-year period.
* $20 million for allowing 21,000 deregistered company accounts, which held $120 million in funds, to remain open, and continuing to charge fees on those accounts.
* $20 million for subsidiary BT Funds management including banned commission payments on insurance premiums.
* $15 million for distributing duplicate insurance policies to more than 7000 customers for the same property at the same time, plus policies to 329 customers who had not consented.
* $6 million for inadequate fees disclosure worth about $10.6 million to at least 25,000 customers.
* $12 million for selling consumer credit card and flexi-loan debt to debt purchasers with incorrect interest rates.