Sites such as Long Cross Woodland, Fonthill Park and Moorend Gardens are among those earmarked for sale, while the fate of a further seven sites is still being considered.
Councillor Gary Hopkins said: "We need to get on with making the investment in parks and green spaces that will come from disposing of these sites. This means investment for new playgrounds and facilities for all age groups." He added that the disposals only represented just over two per cent of Bristol's parks and green spaces.
But the council's former parks manager Alan Barber said that although the principle was a positive thing, 30 per cent of capital receipts made from the sell-offs would not be put towards park improvements.
"They did try to make this 50 per cent, which shows that decisions are being made by a council that does not really believe in what it is doing," he added.
"We hear a lot about the spaces to be disposed of, but too little about how the receipts will be spent. The overwhelming need is for a bigger maintenance budget for parks in the city, not cash-frittering schemes for minor improvements. I am not sure this policy tackles the problem."