New Zealand Rugby makes decision on Shields
NZR had been stalling over Shields' request for permission to join Eddie Jones' team, raising the prospect of a tug-of-war over the highly-rated flank who will move to England to play for Wasps at the end of the Super Rugby season after giving up on being picked for the All Blacks.
But NZR said that after examining the complex case it had agreed to the move even though there were "clear legal grounds to decline".
"We are releasing Brad with our best wishes and we hope to see him achieve his goal of playing international rugby in June," NZR head of professional rugby Chris Lendrum said in a statement.
But Lendrum made it clear NZR were unhappy with the way England's Rugby Football Union (RFU) had handled the matter.
"We are extremely disappointed that the RFU chose to take this unusual step in seeking this release given that Brad has not yet played rugby in England," he said.
Shields is New Zealand-born but eligible for England through his parents and had been expected to feature in Jones' plans for the 2019 World Cup.
But the call-up came earlier than expected, with England looking to select him for the three-Test tour of South Africa, even though his Super Rugby season with the Hurricanes is not yet over.
Lendrum said Shields' contract required he make himself available only to New Zealand teams, meaning there was no obligation to release him.
England's argument was that World Rugby rules requiring clubs to release players for national duty during international windows would have trumped the contract, although neither case will now be tested.