More than 3,000 athletes were due to take part in the Games, which were to be held in Peshawar, the BBC reports.
"Teams are already not willing to come to Pakistan because of the security issues and we don't want a situation where a domestic event is also affected by some incident," said National Olympic Committee president Arif Hasan. He said the new dates in December would also be subject to security concerns clearing.
Pakistan has suffered many attacks by militants in recent months, the BBC says.
