Well, if you choose to make it more attractive, there are always tax incentives you can provide. You can say to individuals that if you earn income at a certain age, you don't have to pay as much tax on it. You can change the nature of the GIS system so that less of the money is taken from people as they work. Those are all options.
I personally dislike the parts of the GIS system which take 75¢ on the dollar rather than 50¢ on the dollar, which is more or less the standard rate: 75¢ on the dollar seems to be a very great disincentive to work.