Lae is a spread-out city with no public transport system to speak of. PMV buses — privately operated minibuses and trucks — run loose routes around town, but they have no fixed schedules and can be confusing for newcomers. They are cheap and widely used by locals.
Taxis are available but should be arranged through your accommodation or a known operator rather than flagged down on the street. Walking is feasible in the central area during daylight — the Botanic Gardens, War Cemetery, and main market are all within a few kilometres of each other — but security is a genuine concern. Do not walk alone after dark, and ask locally about which areas to avoid. Many visitors and expatriates get around by private vehicle, and if you are staying more than a day or two, arranging a car with a driver through your hotel is the most practical option.