Outgoing Australia Post managing director Ahmed Fahour has lashed out at One Nation leader Pauline Hanson for her "ill-informed" and "hurtful" comments about his Islamic faith at his final appearance before Senate estimates hearings.

Mr Fahour and Australia Post chairman John Stanhope fielded many questions on Tuesday about Mr Fahour's controversial $5.6 million salary and why Australia Post tried to keep it secret.

Senator Hanson was one of the loudest critics of Mr Fahour's salary and reacted gleefully to his announcement last week that he would resign, saying the news was "fantastic".

"I'm still on the floor of Parliament, you're unemployed, let's hope you're not going to get in the queues for employment," she said in a Facebook message.