Tutu said there was a need for change in the country.
The African National Congress had been "very good" at leading the country in the struggle to be free from oppression
"They were a good freedom-fighting unit. But it doesn't seem to me now that a freedom-fighting unit can easily make the transition to becoming a political party."
He said the "first thing" the next elected Parliament had to do was to change the electoral system so one was elected on the basis of the constituency, and would be accountable to the electorate.
"Those in Parliament are accountable to their party first rather than the electorate."
Tutu wrote that although the country had the capacity to be one of the most vibrant countries in the world, it had the most unequal society in the world.
"We can't hold our heads up with pride when you think of the levels of violence in our country."
He wrote that South Africans were "amazing". They had been committed to freedom during the political struggle, and had been ready to lay down their lives.
"But now one can point to so many instances of corruption, of unaccountability," he wrote.
"Seeing how standards have dropped is so galling, because it seems to give ammunition to those who would say : 'we warned you that once you had a black majority government you would see a steady decline in standards'."