Low had been expected to announce a decision after a national team coaches meeting that ended on Wednesday but the coach told the German Football Federation (DFB) website that it will now come at the end of April.
Low had pledged never to recall the Schalke 04 striker after he stormed out of a World Cup qualifier against Russia in late 2008 when dropped from the squad.
Kuranyi's impressive form and his goal tally have brought him back into contention, Low had said before the meeting.
"I am fully aware of my responsibility as national team coach but we will not be forced into a decision by public pressure," he said on www.dfb.de.
Germany will unveil their preliminary World Cup squad of 30 players on May 6 and Low will cut it down to 23 by the June 1 deadline.
Kuranyi, 28, is enjoying his best season yet, scoring a personal best of 18 league goals so far with four matches remaining.
The Brazil-born striker has also set up seven goals as second-placed Schalke 04 challenge for their first German championship in over 50 years.
In comparison, Germany strikers Lukas Podolski, Miroslav Klose and Mario Gomez have only scored 14 league goals between them this season.
Schalke coach Felix Magath criticised Low's delay.
"I think it is good that the coaching staff sat down for three days and then decided to wait a little longer," Magath sarcastically told reporters on Thursday.
"If (Low) cannot decide after 30 match-days then we just have to wait until the 34th (final) match-day."
Kuranyi, who has won 52 caps and scored 19 goals for Germany since 2003, last played for his country in September 2008.
Germany have been drawn in Group D alongside Serbia, Ghana and Australia for the World Cup in South Africa starting on June 11.
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