The trials are part of a cyclical law review undertaken by World Rugby every four years which recently involved input from All Blacks head coach Steve Hansen and Chiefs head coach Dave Rennie.
Following a review by World Rugby's Laws Representative Group, the law trials may be considered for a global trial in 2017 and possible adoption in 2018.
"I think it's always exciting to be part of a process that looks to keep the game fresh and relevant. We are particularly keen to trial these laws as we believe they will help make the game safer to play, will be easier to understand, and as a result more entertaining to watch," NZ Rugby's general manager of rugby Neil Sorensen said. He said NZ Rugby wanted to revise the laws around the breakdown to improve safety, and was leading the process, with significant changes to laws 15 and 16. These laws cover the tackle and ruck respectively and see the ruck renamed the "breakdown". These amendments will apply to the Mitre 10 Cup which starts on August 18 and are already being trialled in some premier club games.
Eight provincial unions - Bay of Plenty, North Harbour, Northland, Otago, Southland, Taranaki, Tasman and Waikato - have already elected to implement the law trials during their current premier club rugby season.
The law trials will be in place for the pre-season Ranfurly Shield challenges from Thames Valley, King Country and Wanganui, but these unions have not chosen to include them in their premier games.
There was an earlier proposal to consider the use of two referees in games, however, after conversations with World Rugby it will not proceed in this round of law trials.