Officials have said that further investment in Kiwibank would give the Government a good return.
Papers obtained under the Official Information Act document a meeting in January last year between State-Owned Enterprise ministers and the chair and chief executive of New Zealand Post, Kiwibank's parent company.
During the meeting, the company signalled an intention to ask for a capital injection of $100 million from the Government.
The papers show the Crown Company Monitoring Advisory Unit (CCMAU) told the ministers that the companies would create long-term value for the Government if it invested in them.
New Zealand Post chairman Jim Bolger says discussions with the Government about a possible equity injection are continuing.