The National Construction Code sets minimum slip resistance classifications, assessed under AS 4586, for stair treads, nosing strips, landings and ramps. For example, stair treads and nosing strips generally need at least P3 where dry and P4 where they may get wet, with higher ratings for steeper ramps. For other areas, the Standards Australia handbook SA HB 198:2014 recommends classifications based on how the space is used. Your certifier and the current NCC are the final reference for your project.