CANBERRA, Australia—The Australian government has moved closer to selling the national rail network, which could if agreed add to a wave of privatizations of properties from ports to power assets that has attracted international interest.

With the budget hole growing—updated figures released Tuesday are expected show a deficit 3 billion Australian dollars (US$2.2 billion) wider than previously estimated—Finance Minister Mathias Cormann said he had appointed advisers to make recommendations about the government-owned Australian...