All routes into Mungo National park are good quality, two-wheel-drive unsealed roads. You do not need a 4WD to drive them in good weather. However, there are often road closures during or after wet weather.
Since road conditions can change quickly in the outback, before you travel you should check what roads are open or closed within Mungo National Park, as well as the roads leading to the national park from nearby towns. This advice can be obtained from Balranald, Wentworth and Mildura visitor information centres.