The ERC Board have approved an extra two players per squad for the pool stages - up from 34 to 36 - and then up to three additional players for those teams who qualify for the knock-out stages.
"Clubs approached ERC and asked us to reconsider squad sizes due to the challenges and length of the tournaments, in particular when it came to rtounds five and six," said ERC chief executive Derek McGrath.
"They said injuries were playing an increasing part in denying them fielding their best teams and, after considering the requests and receiving feedback from the clubs, the board of ERC approved an increase in the squad size to 36 players with the stipulation that 10 of them should be front-row forwards.
"For those clubs reaching the knock-out stages they can add up to three new players without dropping any player from their original squad. Previously they could add two new players in any position and if the third was a front-row forward he had to replace another front-row forward who could then take no further part in either ERC tournament."