We assume that because of the extremely cold weather this year that some of the new growth is emerging yellow, bronze or even brown; in the past we have observed that as this growth matures it returns to a green colour. The Wollemi Pine starts to need copious amounts of water when this flush of growth arrives. It may also be worth applying some slow release fertiliser into the soil around your tree.
If there is brown tipping on the leaves and you consider it unsightly it can be trimmed off using a sharp pair of scissors, this will have no adverse affect on the overall health of the tree. If the branch is dead it is best to remove it, for large diameter stems and branches (greater than 5cm) use sterile, sharp pruning equipment to match the size of the stem or branch being pruned. We have however seen more mature trees, having lost lower branches naturally start to produce new growth from lower down the trunk and this could be the case with your tree.