The by-election was to be held on April 12.
The EC notification said the state administration apprehends that “violent attempts” can be made by miscreants to thwart the poll process.
It pointed at large scale violence which took place in Srinagar on Sunday during a similar bypoll.
June 1 has been set as the date by which election process should be completed in Anantnag.
The long period has apparently been given keeping in mind the possibility of repoll that may be held there.
The Anantnag seat fell vacant in June last year after Mehbooba Mufti won the assembly polls and resigned from the Lok Sabha.