It also announced its preliminary results for the third quarter which saw revenue at between US$802 million and US$804 million, a fall of 9% from the corresponding quarter in the previous financial year.
The chapter 11 filing was done after the company extended a string of 10 years of losses.
In a statement on Monday, Peter Chidiac, Avaya's managing director in Australia and New Zealand, said while the US parent company had been working through the chapter 11 process, business had progressed strongly in the A/NZ region.
“Over the last two years, we have been vocal about the transformation of the A/NZ business; we recognised the need to restructure in order to align to the demands of the A/NZ market and deliver software and services that local organisations need and ensure the success of our customers.
“The transformation is proving positive – last year we reported that Avaya A/NZ closed its fiscal 2016 with its strongest quarter in 12 quarters, and the business has continued to build from there.”
Avaya also announced a change of leadership on Monday, with Jim Chirico being appointed as chief executive from 1 October.
The preliminary earnings for 3Q were flat compared to the second quarter. The company said that final results would be announced next week.
Avaya is owned by Silver Lake and TPG Capital which took it private after buying the firm in 2007 for about US$8 billion.
The company was originally part of AT&T and sells phones and other telecommunications equipment, plus hardware and software used in call centres.