Davies picked up a rib problem whilst playing for his club this weekend and Wales Team doctors have ruled out Bennett due to a nerve complaint in his neck.
"Huw damaged nerves in his neck three or four weeks ago and medical advice tells us that he needs to undergo a period of rest, preventing further impact to allow the condition to resolve," said Jenkins. "Gareth Williams was put on standby to replace him last week and we have taken the decision to take Gareth on the plane based on medical advice around Huw.
"Gareth has put together a run of decent performances for his region and he will bring a level of experience that will be vital to the squad. We have also asked Matthew Rees to join the tour, rather than remain at home for our summer training camp, after losing someone of Mefin's experience. We need to factor in consistency at lineout and scrum on this tour and it will prove vital to have two players who have international experience in that specialist position.
"Tom James is a hot prospect, but we wanted to make sure he came through the weekend's action before bringing him in.
"It's unfortunate that we didn't get a chance to see Gavin Henson in action at the weekend, but we are confident he is fit and will be available to us and his issue at the weekend was more of a conditioning one. His task now is to get himself 100% right in the time available and show us in training that he is back up to his own high standards."
Matthew Rees (Scarlets)
DoB: 09.12.80 Ht: 6'2" / 1.88m Wt:15st 11lbs / 100kgs
International record: 10 caps (W3, L6, D1; 10 pts - 2T)
Gareth Williams (Blues)
DoB:19.12.78 Ht: 5'9" / 1.76m Wt:15st 6lbs / 98kgs
International record: 5 caps (L5)
Tom James (Blues)
DoB:17.04.87 Ht: 6'2" / 1.87m Wt:15st 1lb / 96kgs
International Record: Uncapped