Martin "retired" from his post on June 29, after four years at the helm of NZF. His turbulent tenure culminated in NZF being forced to issue a public apology to former Ferns manager Claire Hamilton after Martin had earlier claimed her departure was due to performance issues.
Hamilton had reportedly raised concerns about issues during the Ferns' disastrous camp in Spain in March.
Heraf resigned last Tuesday. His dual positions at NZF (he was also national technical director) had seemed untenable after 12 members of the Ferns wrote letters of complaint about his conduct, adding they would be unavailable for New Zealand while he was in the job.
Martin has refused to respond to requests for comment since his exit, although it's understood he will be participating in the ongoing review.
NZF president Deryck Shaw declined to detail the specific arrangements around the exits of Martin and Heraf, nor confirm if there were settlements paid to either.
"It's an employment process and I can't comment on the details because of that. It's an agreement between the two parties," Shaw told the Herald on Sunday. "They have both resigned, and left within the terms and provisions of their contractual arrangements. We had a duty of care to meet those, which we have done."
Martin's contract was drawn up by the previous board and chairman, while Heraf's contractual arrangements were solely negotiated by Martin himself, without input from the board.
The review, conducted by leading employment lawyer Phillipa Muir, is expected to cost in excess of $100,000. There will also be other associated costs, plus the settlements paid to Martin and Heraf, which will lead to a sum total that could hit $400,000.
Shaw couldn't comment on specifics, though acknowledged the review was "not a cheap exercise".
"That's the reality of the situation," he said. "We have costs and obligations we have to meet but we are careful around our financial management.
"We were ahead of budget last year but we need to make sure we spend every dollar wisely."
Shaw insisted the competitions and national teams programme would not be affected by the outlay.
"The costs that we have got that are non-budgeted costs will be met, but the commitments we have in the game will be met as well," said Shaw. "There won't be anything compromised, we are very clear on that.
"We have been prudent as an organisation and we have reserves. It's helpful at times to have reserves when times are challenging."
The Herald reported earlier that several other people who worked with Heraf in the Ferns' environment will also come under close scrutiny in the investigation and that more heads are expected to roll.