RFU chief executive Steve Brown says Brad Shields will tour South Africa with England in June despite New Zealand Rugby's protests.
The Hurricanes forward is set to move to Wasps at the completion of his Super Rugby contract, and is eligible to represent England in international rugby.
Shields, who qualifies through his parents, will become eligible for England selection when his Super Rugby contract expires.
The New Zealand Rugby Union have countered that his New Zealand rugby contract takes precedence, but Brown says according to World Rugby rules, Shields will be available for England selection.
The tug-o-war, it seems, is set to continue.
"Regulation nine is clear and understood by everybody," Brown told The Times.
"If we find ourselves in that situation we will rely on the World Rugby regulation."
NZR chief executive Steve Tew, though, believes 'the World Rugby regulations don't apply per se because he's committed himself to New Zealand'.