Westpac's mobile phone push notifications to alert customers about opportunities to earn bonus interest on their savings has managed to add $21 million into the bank accounts of those who've engaged so far.

The alerts are currently being rolled out to customers with a Westpac Life Savings account. So far, about 107,000 customers have acted on the prompt, earning an average of $201 each in interest, totalling $21 million.

Customers can earn bonus interest on their Westpac Life savings account each month when they grow their balance. Customers under 30 can earn additional bonus interest when they use their debit card five times or more in one month.

Westpac has also introduced alerts in online and mobile banking which notify customers with an eSaver account before their introductory bonus rate expires.

"We want to make it easier for our customers to get the most out of their hard-earned savings, particularly in a high cost of living environment. These prompts are designed to help customers better understand opportunities to earn bonus interest and allow them to act quickly," said Mandy Rutherford, Westpac Managing Director of Cash & Transactional Banking, adding she was pleased to see so many customers growing their savings balances and building better savings habits.

"This is part of our continued investment in digital tools that help our customers make more informed decisions about their money."

Customers can earn bonus interest on their Westpac Life savings account each month when they grow their balance. Customers under 30 can earn additional bonus interest when they use their debit card five times or more in one month.

Westpac's banking app features a range of personal financial management tools, including the ability to block direct debit payments from a particular company.