According to an EC official, the poll panel in an order issued around midnight rescinded a notification issued earlier on holding the bypoll on May 25.
Sources said the Election Commission had sought deployment of around 740 companies of paramilitary personnel for the bypoll.
The Home Ministry, however, said it could only provide around 300. A company usually has around 100 troopers.
The state government had earlier sought cancellation of the bypoll due to the prevailing law and order situation in the Kashmir Valley.