A national stadium is a stadium that typically serves as the primary or exclusive home for one or more of a country's national representative sports teams. The term is most often used in reference to an association football stadium. Usually, a national stadium will be in or very near a country's capital city or largest city. It is generally (but not always) the country's largest and most lavish sports venue. In many cases, but not all, it is also used by a club team. Many countries including the United States, do not have a National Stadium designated as such.
Whilst Australia does not have an "official" national stadium, its two biggest stadiums alternate hosting large events:
Melbourne Cricket Ground (Australian rules football, cricket, and major soccer events) - often seen as the de facto national stadium due to historical links as well as being the current largest in Australia. As it is the largest stadium in Australia (with a capacity at 100,000), and is located in Melbourne, the sporting capital of Australia, the MCG is generally considered Australia's national stadium, although it alternates between ANZ Stadium hosting major events.
ANZ Stadium, formerly known as Stadium Australia, the 2000 Sydney Olympic Stadium (rugby league, rugby union, football (soccer) and occasional Australian rules football). There exists a popular rivalry between ANZ Stadium and the MCG due to lasting rivalries between football codes and the respective cities. There was a strongly implied claim to being the new national stadium when it opened in 1999 with the name 'Stadium Australia'. The only major sport that it does not host events for is cricket, as the Sydney Cricket Ground is a traditional home for the sport.
In the case of rugby, the national team plays test matches throughout the country, but it exclusively uses Stade de France for its fixtures in the Six Nations Championship.
South Africa does not have a national stadium for rugby union. The Springboks play at several venues throughout the country, four of which seat over 50,000.