Launched August this year by state utility and grid operator Eskom, the Round 4 call for renewables bids includes 590MW of wind power.
Wolsley Barnard, director-general of the country's energy department, told delegates at Cape Town's Windaba wind conference this week that meeting the 24 November deadline was "doubtful".
Barnard pointed out that Eskom was forced to pay owners of some completed projects for power they could not produce due to grid improvement delays.
He was unable to give a new date, only stating it would be "as soon after as possible".
Barnard also told delegates that the government was studying a reduction of around 10GW to the 67.8GW 2030 installed electricity capacity national target. The aim was set in the Integrated Resource Plan (IRP) 2010-2030.
Grid issues have already caused the delay behind securing financial closure on around 878MW of round 3 projects.
The seven projects, which were selected under round three of South Africa's renewable energy independent power producers programme (REIPPP), were supposed to reach financial close on 30 July.
However, Eskom is concerned that it does not have sufficient funds to complete the required upgrades on time, making it impossible for the government and bidders to sign off on the projects.