Rugby's new rich class will be those players who have never quite made the All Blacks.

It is older players who either never made test football or who had a brief taste of it who are going to be the big winners in the collective contract agreement shortly to be unveiled.

Players such as Ryan Crotty, James Parsons and Hika Elliot, who are most vulnerable to overseas offers, are the sort of men New Zealand Rugby is desperate to keep. These older players, who have either been part of the All Blacks or close to, bring the knowledge and professionalism that is critical in Super Rugby teams where the average age of squad members in New Zealand is 25.

The vulnerability of this older group was illustrated last week when long-serving Crusader Andy Ellis announced he will leave for Japan next year and fellow former All Black, Cory Jane, is likely to head to Asia.

Jane and Ellis bring a depth of knowledge and skills to Super Rugby that are vital in not only guiding the younger generation, but also give their teams trusted decision-making and accuracy on the field.

But typically, New Zealand Rugby player services manager Chris Lendrum, estimates that older, experienced players in New Zealand can earn double offshore. Someone with five years' experience in Super Rugby and a handful of All Blacks caps can earn around $250,000 a season playing here. If they headed offshore, they would most likely be earning a similar figure - but in pounds or euros. Japan, too, is an increasingly lucrative market for players with a bit of long service.

There have been a handful of cases in recent seasons which have fallen well outside the norm to demonstrate how in demand experienced New Zealand players are. Colin Slade, Tom Taylor and Charles Piutau all received offers that were significantly more than double to that on offer in New Zealand.

New Zealand Rugby wanted to keep all three but they couldn't get near the offers that came out of Europe. Slade was reportedly offered $750,000 a season to join Pau, Taylor $600,000 to end up at Toulon and Piutau around $1 million a season to join Ulster.

These sorts of offers are not as uncommon as New Zealand Rugby would like and chief executive Steve Tew warns that the egos of French club owners, in particular, make it is likely that these sorts of numbers will be seen again for other senior players.

Negotiations are ongoing between NZR and the New Zealand Rugby Players' Association to finalise the latest collective agreement. Although both parties are sworn to secrecy over the detail, Lendrum has made clear that the key priority will be to better protect senior peripheral All Blacks from leaving.

The broadcast deal is believed to be worth around $350 million over five years - a 100% lift on the agreement that expired in 2015. The players directly benefit from this increase, with about 37% of that money paying their salaries.

In addition to earning higher basic rates of pay, it is thought that a pot of money will be put aside to incentivise older players to stay. For instance, it may be a massive bonus payment kicks in if they stay in New Zealand for a certain number of years.