I think herding type dogs are more commonly used in NZ than Oz for dogging pigs. Here you might see the odd blue heeler, or more often a cross with something to give them a bit more size and muscle, and you'll see some dog packs that have smaller or lighter dogs as finders, but the preference here seems to be to have dogs in the pack which will go in and get a good hold on the pig, by an ear or something, so that you can walk up behind it and stick it (not slash its throat, stick it in the heart). I've done it myself, and it has always been with a couple of well-built dogs to hold the pig. There are any number of bull terriers, pitbulls, mastiffs and the like used for this.
There's also one breed developed locally especially for finding, running down and holding pigs, the Bull Arab, which was developed by combining GSP (for a good nose), deerhound (for long legs and speed) and mastiff or something similar for size and strength. They were also bred to be trainable and reliable with kids and other dogs, and if the one sitting panting at my feet (we just got back from a run) is any guide they meet that too. He's bloody huge, but the most easygoing of dogs. Some of the other dogs used on pigs can be a bit too aggro to have around.
