Voters in the 9th congressional district must select a replacement for Nathan Deal in the U.S. House and fill the legislative seats held by state Sen. Lee Hawkins and Rep. Tom Graves.
All three elections had been set for April 27.
But Perdue spokesman Bert Brantley said Wednesday that the secretary of state’s office was concerned there was not enough time to get ballots returned from military members stationed overseas.
The qualifying period for candidates wishing to run will remain March 29-31.
Deal left Congress to pursue the Republican nomination for governor. Hawkins and Graves resigned to run for Deal’s seat.
In addition to Graves and Hawkins, eight other Republicans, two Democrats and one independent have previously announced plans to run for Deal's seat.