But despite the injury list, which also includes Peter O'Mahony' Luke Fitzgerald and brothers Dave and Rob Kearney, van der Merwe believes that the Irish Guinness PRO12 forward contingent will set up an enthralling encounter.
"The Irish take pride in their pack of forwards. There are a lot of good locks in Ireland' but we have them too," he said.
"There is an Ultan Dillane' who plays for Connacht' who is a young' massive and very good player. They have more experience in Devin Toner' a tall lineout specialist. It will be a great second row battle.
Van der Merwe has the inside scoop in both camps having played one Test for South Africa as well as domestic rugby for the Lions, while he arrived at the Kingspan Stadium back in 2014.
The 33-year-old lock has spent most of the Guinness PRO12 season alongside Iain Henderson, and while he concedes the Irish injuries will be a factor, the visitors should not be underestimated.
"They are a side that has improved a lot. We saw in the November Test last year when they beat us what they are capable of. They have also beaten Australia' proving that they're very successful'" he said.
"Joe Schmidt is a very good and intelligent coach' with a very fit squad. The Irish are a proud nation' and they put an emphasis on first-phase ball and are good scrummagers."
He continued: "Ireland will come out with everything they've got. But I'm quite confident that the Boks will win the series. Some of the games may be close' but the Boks should take it."
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