Hard to bloody well kill those things; I think I'd cut it down, dig out the stump and keep on poisoning the succers with either Zero 490 or Yates tree and blackberry killer until no more come up.

I was hoping to avoid the cutting it down part, is it possible?

Well you can kill it by ringbarking it: Take a axe or tommahawk and cut all around the trunk and take out, say, and inch of bark down to the hardwood. That'll prevent the transfer of neutrients up and down the tree and it'll die. If you leave the dead tree in the termites (white ants) are more than likely to infest it and most other timber near by. For that reason alone, I'd dug it out. The succers you'll still have to take care of as they come up.

no there is no way around it. youll need to take it out anyway or it will be unstable and dangerous to have around ,or will attract termites as funnelweb suggested

looks like I'm cutting it down. thanks for the feedback

would like to know how you got on i have the same problem beutiful tree but had to chop it now its growing suckers every where under the house in the niegbours just pulled out roots this morning the size of a fire hose tried zero round up and tree and blackberrie killer the bloody thing just will not die trying plain old salt now