The consumer bank arm of Westpac has registered cash earnings of A$1.72bn for the first half fiscal year 2018, an increase of 12% on year-on-year basis.

The bank attributed the rise in earnings to good balance sheet growth, disciplined margin management and reduced impairment charges.

For the period ended 31 March 2018, the division’s net interest income stood at A$4.04bn, up 8.9% compared with A$3.68bn in the corresponding year ago period.

Overall, the banking group reported cash earnings of A$4.25bn ($3.1bn) for the first half, an increase of 6% compared to A$4.01bn ($3bn) reported a year ago.

The banking group’s statutory net profit for the period ended 31 March 2018 was A$4.2bn, up 7% from A$3.91bn in the corresponding year ago period.

On a reported basis, net interest income increased 9% to A$8.28bn from A$7.61bn last year, while non-interest income dropped 9% year-on-year to A$2.87bn. Compared to the previous year, impairment charges slumped 20% to A$393m.

Operating expenses were A$4.72bn, up 2% from A$4.63bn in the previous year.

The banking group’s common equity Tier 1 capital ratio stood at 10.50% at the end of March 2018, as against 9.97% a year earlier.

Commenting on the performance, Westpac Group CEO Brian Hartzer said: “This is a good quality result built on consistent performance and a disciplined approach to growth and returns.

“Over the past 12 months we have continued to make progress on our service-led strategy, including adding over 370,000 new customers and making it easier for customers to manage their money.

“We have invested over $1.3 billion in delivering new services to customers and upgrading the bank’s infrastructure.”