Singapore needs to retrofit at least 6,500 buildings over the next 20 years for it to reach its green building target, local media reported Monday.

The Singapore Green Building Council projected the figure, which will enable Singapore to reach its target of "greening" at least 80 percent of its buildings by 2030, local TV broadcaster Channel News Asia reported.

Singapore currently has 500 green buildings which forms 8 percent of the building stock.

So far, some 10 existing buildings are in the midst of retrofitting.

For them, the benefits go beyond saving the environment and being energy efficient, with building owners reaping savings of half to one million Singapore dollars (0.37 million to 0.75 million U.S, dollars) a year.

Most retrofitting processes typically involve improving the air- conditioning and lighting systems, lifts and the facade.