Some northern hemisphere unions are unhappy with the changes
Southern hemisphere unions South Africa, New Zealand and Australia will trial two of rugby's experimental new laws in the 2008 Tri-Nations matches.
The two new laws for the Tri-Nations will permit the pulling down of the maul and remove the requirement that teams match numbers at the lineout.
New Zealand host South Africa in Wellington on July 5 in the opening Tri-Nations fixture of the season.
New law changes are being trialled globally for a year.
"We believe the laws we will play in the nine matches of the Tri-Nations will provide a rigorous examination of the most fundamental of the ELVs," said Jonathan Stones, chief executive officer of the South Africa New Zealand and Australia Rugby (SANZAR).
The changes are being trialled from grassroots to Test level with 13 of the 23 Experimental Law Variations (ELVs) in use in the southern hemisphere to be introduced.
Some other ELVs will be trialled in an unnamed northern hemisphere event.
A further seven ELVs have been referred back to the International Rugby Board's laws group for further analysis.
The ELVs were partially trialled by teams from Australia, New Zealand and South Africa in this year's Super 14, but some northern hemisphere unions have expressed reservations on safety grounds.
Changes to be trialled worldwide include:
Players can defend a maul by pulling it down.
Introduction of an offside line five metres behind the hindmost feet of the scrum.
No restriction on the number of players who can participate in the lineout from either side (minimum of two).
The receiver in a lineout must stand two metres back from the lineout.
Flags are no longer considered to be in touch in-goal except when a ball is grounded against the post.
Further ELVs to be trialled in an elite northern hemisphere competition, expected to be the European Challenge Cup, include:
For all offences other than offside, not entering through the gate, and Law 10 - Foul Play, the sanction is a free kick.
If the ball is unplayable at the breakdown, the side that did not take the ball into contact will receive a free kick.
If a maul becomes unplayable, the team not in possession at the start of the maul receives a free kick.