New guidelines agreed to by World Rugby that will limit players to 30 full games a season to protect their health were hailed Wednesday as a "landmark moment" for the sport.

Under the new regulations, players will also be entitled to rest times after international selection and at least a five-week off-season.

"As with all World Rugby policies, these guidelines are informed by the latest science and expert opinion," said World Rugby chairman Brett Robinson in a statement.

"Our hope, over time, is that unions and competitions reach local agreements to best serve the individual circumstances of players.

"In the meantime, these guidelines provide a solid backstop. As we grow our sport, players can be sure that they are being well supported by their clubs, unions and at the very top of the game by World Rugby."

The player load guidelines cover the elite men's and women's game around the world, with the hope that they help reduce injuries and concussions.

They are supported by leagues, unions, independent experts and the International Rugby Players Association (IRPA).

"This is a landmark moment for rugby," said IRPA chief Omar Hassanein.

"These guidelines put player welfare and safety at the heart of the global game and ensure that athletes can perform at their best while protecting their long-term health."

IRPA chief of rugby operations Conrad Smith added that the new rules balanced elite performance and player well-being with the commercial realities of the game.

"Our efforts in the past have focused on player behaviour, with harsher sanctions for foul play and lowering the tackle height," he said.

"While we support these efforts we equally acknowledge that these have had little material difference on numbers of concussion and Head Acceleration Events (HAEs).

"The most material impact we can have on player injury rates is through management of player load, specifically through managing match numbers and contact training."

Having new guidelines in place was conditional on World Rugby approving the new Nations Championship, which can now begin as scheduled next year.

The Nations Championship is planned to be a biennial international men's competition consisting of 12 teams, including the current Six Nations and SANZAAR sides.