If you're certain that the top is healthy and growing well, with no signs of wilting, browning or unhealthy growth, then you can remove them if you want to. These sometimes occur when there's been damage to the trunk or growing tip, which wouldn't be a surprise after last winter, so if the top isn't healthy, you'd be best off cutting the trunk down to where the new growth is and letting it grow on. Even if the top is healthy, you can leave the stuff at the base to grow on if you like.
This assumes your plant is actually Cordyline australis, the australian cabbage palm.

Thank you for the information, the tree looks healthy, it has plenty of green leaves at the top and a bushy flowery type shoot growing on top