In his 2012 Medium-Term Budget Policy Statement, tabled in Parliament, he said growth rates of certain key groups, such as those eligible for child support grants, would decline.
This meant less money would need to be budgeted for social grants over the next 20 years.
"Similarly, the school-age population is beginning to fall, underscoring the need to improve the quality of education, rather than increase the quantity of resources available."
Gordhan said a long-term fiscal report, which would include data from the 2011 Census, would be issued early next year.
The report would model the impact of some key policy changes, such as the introduction of national health insurance and the National Development Plan.
Preliminary fiscal observations would be released next month.