Abbo Moro said he had been advised by the military that enough troops would be available in six weeks’ time to secure the presidential ballot.
Officials say they delayed the vote to 28 March because troops needed for security are fighting the militants.
Opposition candidate Muhammadu Buhari has made a plea for calm.
But he said the independence of Nigeria’s electoral commission had been “gravely compromised” by the decision to postpone the elections.
Meanwhile Boko Haram launched its second attack in three days on neighbouring Niger, targeting the border town of Diffa on Sunday. At least one person was killed in a blast in the town’s market.
Saturday’s decision to postpone the presidential poll was welcomed by the ruling party of incumbent President Goodluck Jonathan though the US said it was “disappointed”.
Parliamentary elections due to take place on 14 February have also been postponed to 28 March, and elections for state governors and assemblies slated for 28 February have been moved to 11 April.
Nigeria’s opposition says the decision to postpone the 14 February presidential elections by six weeks is a “major setback for democracy”.
The election commission said it moved the poll date because troops needed to protect polling stations were being deployed to fight Boko Haram.
The postponement was welcomed by the ruling party, but the US said it was “disappointed”.
Nigeria has been battling an insurgency by Boko Haram in the north-east.
Thousands of people have died as a result of the militant group’s insurgency over the past six years.
Boko Haram has also started attacking Nigeria’s neighbours: on Sunday, for the second time in three days, the militants attacked the Niger border town of Diffa.
At least one person was killed in a blast in the town’s market, with some witnesses saying a suicide bomber was responsible.
The chairman of the opposition All Progressives Congress (APC), John Odigie-Oyegun, said the move to delay the elections until 28 March, announced late on Saturday, was “highly provocative” and “a major setback for Nigerian democracy”.
However, he urged Nigerians to “remain calm and desist from violence and any activity which will compound this unfortunate development”.
Former military ruler Muhammadu Buhari from the APC is challenging incumbent President Goodluck Jonathan, who heads the People’s Democratic Party (PDP), in the upcoming elections.
Correspondents say it looks set to be a tight race between the two.
Opposition officials accuse the military of forcing the electoral commission into the delay to help the sitting president’s campaign.
However, Attahiru Jega, head of the election commission, said the postponement was necessary as he had been told that troops would not be available to protect voters as they were too busy conducting operations against Boko Haram.
“The commission cannot lightly wave off the advice of the nation’s security chiefs,” he said.
Culled from www.bbcafrica.com