Balkan Insight reports that this follows new legislation, known as the Law on Public Information, that was approved by the government on July 27 and is likely to be adopted by parliament this week.
The tax, which will not exceed RSD500 (€4.28) a month, is seen as paving the way for the state to withdraw from media ownership, thereby reducing political interference in broadcasting.
Although RTS and RTV were previously funded by subscription fees collected through electricity bills, their revenues continued to decline and in 2012 the new government said it would step in to fund the channels.
However, they will now only be dependent on the state budget for this year and 2015, before the new law comes into effect.
Serbia has acted under pressure from Brussels, which expressed concerns about the independence of the two channels.