Cape Town - Wales added Cardiff duo Cory Allen and Tomos Williams to their injury-hit squad on Monday.Allen, who has four Wales caps, has been called up after Newport Gwent Dragons centre Tyler Morgan was released following a hamstring injury.
Williams, an uncapped scrum-half, comes in as cover for Rhys Webb, who suffered an ankle injury in Saturday's defeat to Australia and is a doubt for the rest of Wales' November Tests.
"Wales have called Cardiff Blues duo Cory Allen and Tomos Williams into their 2016 Under Armour Series squad," a statement on the Welsh RFU website read.
Wales will look to bounce back when they face Argentina in Cardiff on Saturday after being thrashed 32-8 by Australia last weekend.
The Wallabies scored five tries in their 12th successive victory over shell-shocked Wales.
"I've never seen stats so dominant in one side's favour," Wales defence coach Shaun Edwards said.
"It's incredibly difficult. There are more and more tries being scored in modern day rugby but we can defend better than we did and I'm incredibly determined.
"The tackling wasn't too bad. First and foremost we lost the advantage line."
Wales are also due to host Japan and South Africa later in November.