Tyro Payments has announced the resignation of chief executive Gerd Schenkel eight months after his appointment in late October 2016.
Mr Schenkel, who founded NAB's online banking arm UBank, was recruited to oversee a "significant growth program" for the company.
As a result of the departure, Tyro non-executive director Rob Ferguson has been appointed acting managing director while the company searches for a suitable replacement.
Separately, Tyro has announced that founder and former chief executive Jost Stollmann will become a non-executive director.
Mr Stollmann's role was changed from chief executive to executive director upon Mr Schenkel's appointment in October 2016.