"We're four years on from there and half that time has been disrupted by Covid ...
"I know there will be people who will have a view that we should have done this earlier and I'd really acknowledge that.
"But we knew going into a Rugby World Cup year, a year where we were launching Super Rugby Aupiki and a year where we're simply going to be asking much more from our leading women's 15s players than we have in the past, that this was the right thing to do now."
Around $2 million was being invested from NZR's player payment pool to pay the retainers for the new contracts.
Assembly and appearance payments would be on top of that, while Lendrum said the new structure also meant increased contribution to the players' savings scheme and legacy fund.
He said the Black Ferns-contracted players would also be paid for their involvement in the new Super Rugby Aupiki competition, with other players in the competition also receiving payment.
Lendrum also confirmed Black Ferns coach Glenn Moore and the team's selectors had been involved in the process to select which players would receive the new contracts.
Moore had been under the spotlight after Black Ferns player Te Kura Ngata-Aerengamate last month alleged on social media he had contributed to her having a mental breakdown.
The allegations sparked an ongoing independent culture review into the Black Ferns environment, but Lendrum defended Moore's involvement in the contract decisions.
"I don't think from a process point of view it's concerning.
"Those coaches are our experts, they're paid as part of their role to identify and select squads.
"Clearly the review ... is probably going to contain some important recommendations for us moving forward but that's still [ongoing].
"I don't want to pre-empt that and, in the meantime, there is important business to get down to for the players, which is to commence this upgraded programme. They need certainty about where they sit contractually in order to do that."
The new contracts not only came in the wake of an end-of-year tour where the Black Ferns were comprehensively beaten in two matches each against England and France, but in a year which New Zealand would host the World Cup.
Lendrum said the high level the English and French teams had reached was "absolutely" an example of what NZR's increased investment could do for the Black Ferns.
"The [Black Ferns] have been the high water mark for women's rugby for most of their existence [but] there was a really clear line in the sand drawn in November about the standards our players, management and support staff need to get to in order to be the best in the world again.
"We're not there at the moment but we hope to be within 12 months and then consistently thereafter."
