Monkeytoe recommends a cage on ladders 3.5m and above as a guideline, however code does not strictly require it until 6m.
Monkeytoe recommends a mid/change-of-direction landing every 6m on caged ladders in compliance with AS 1657, however within the NZBC there is allowance to go to 9m without a mid/change-of-direction landing.
Learn which access type is compliant at which roof pitch. Walkway access, stair access or ladder access?