As per the previous provisional list, the Prime Minister was scheduled to speak a day earlier on September 27.
The changes are believed to have been made to accommodate Singh's schedule to meet US President Barack Obama.
The two leaders are expected to hold meetings at the White House followed by a working lunch on September 27.
After his meeting with Obama, Singh is likely to leave Washington for New York the same evening.
PM Singh will be meeting US President Barack Obama on Sept 27.
Pakistan's new Prime Minister Nawaz Sharif would address the UN General Assembly on September 27. This would be his first address to the world body in his second term.
In fact, Sharif would be addressing the General Assembly at a time when Obama would hold meetings with Singh.
Obama would address the UN General Assembly on the first day of the start of the general debate. He would be the second speaker after speech by the Brazilian President.
Sri Lankan President Mahinda Rajapaksha is scheduled to address the assembly in the same session as that of Obama.
Newly-elected Iranian President Hassan Rouhani has been scheduled to address the Assembly on the very first day but in the afternoon session, along with the Bangladeshi Prime Minister and 16 other heads of State.