Algeria dwarfs Oceania: about 2,322,788 km² km² against 8,600,000 km² km². At true size Algeria is about 3.7× larger — the whole of Oceania fits into Algeria roughly 3 times.
The old Mercator map treated both about equally (1.3× vs 1× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
Algeria fits 3× into Oceania.