The elections had been scheduled for Jan. 8, but Qazi Mohammed Farooq, head of the election commission, said it would be impossible to hold the polls on that day.
"For a few days the election process came to a complete halt," he told reporters. As a result, the poll will be held on Feb. 18, not Jan. 8, he said.
Officials with the opposition parties of former prime ministers Nawaz Sharif and Benazir Bhutto say they will contest Pakistan's elections next month.
Talat Masood, an independent political analyst judged the delay was "mostly about politics."
"The (election) problems are only confined to a few districts. Musharraf naturally thinks if a hostile parliament comes in he has no future."
The opposition is likely to accuse authorities of postponing the polls to help the ruling party, which is allied to President Pervez Musharraf. Many believe Bhutto's party could get a sympathy boost if the vote takes place on time. Bhutto had accused elements in the ruling party of plotting to kill her, a charge which it vehemently denies.
"We reject this delay outright," said Sen. Babar Awan from Bhutto's party, the most powerful opposition group. "Musharraf fears outright defeat. If this election process is jeopardized, they (our followers) may protest again and there is a chance of riots."
The party of Nawaz Sharif, the leader of another opposition party, accused Musharraf of wanting a delay to allow anger over Bhutto's death to evaporate. "Right now they are the target of public hatred" said Ahsan Iqbal, a spokesman for the party.
Sen. Tariq Azim, from the ruling party, said the opposition was "turning a blind eye to realties on the ground" following the assassination, but stressed the ruling party had not asked the election commission for any delay.
Musharraf said Wednesday that Bhutto's death was a great tragedy for the nation and blamed "terrorists" for her assassination.
In a nationally televised address, Musharraf said he was grieving as much as the rest of Pakistan over Bhutto's slaying in a suicide attack after a campaign rally last Wednesday.
"The nation has experienced a great tragedy. Benazir Bhutto has died in the hands of terrorists. I pray to God almighty to put the eternal soul of Benazir at peace," he said.
The killing of Bhutto, a former prime minister, triggered three days of nationwide riots that killed 58 people and caused tens of millions of dollars in damage. Bhutto's home province of Sindh was especially hard hit and the army was called on the streets. Ten election offices were burned.
The polls are seen as crucial to restoring democracy after eight years of military rule and following a six-week state of emergency that Musharraf declared in November.
CBS News correspondent Sheila MacVicar reports that hours after she was murdered, Bhutto was due to meet two American lawmakers, and
she planned to give them a report compiled by her own intelligence contacts alleging misuse of U.S.-supplied computers and money, and vote rigging by Musharraf's government.
Sen. Latif Khosa, a lawmaker from Bhutto's Pakistan Peoples Party, said she had planned to give U.S. Sen. Arlen Specter of Pennsylvania and U.S. Rep. Patrick Kennedy of Rhode Island a report outlining complaints on "pre-poll rigging" by Musharraf's government and the military-run Inter-Services Intelligence Directorate.
Khosa told MacVicar the government had a U.S.-supplied supercomputer, "which has the capacity to hack any computer, and that is connected with the (elections) commission to overturn the result."
Khosa said he did not know if Bhutto's killing was linked to her plans to release the document. Officials at the Information Ministry and the Interior Ministry declined comment. The government has denied charges of vote rigging and said it had nothing to do with Bhutto's death.
The dossier outlined several instances of electoral interference, including one case where an officer from the intelligence services sat nearby as an election official rejected nomination papers from opposition candidates, Khosa said. Another official stopped a candidate from filing his nomination in the southwestern Baluchistan province, said Khosa, who wrote the report as head of the party's election team.
"The elections were to be thoroughly rigged, and the king's party was to benefit in the electoral process," he said, referring to the pro-Musharraf Pakistan Muslim League-Q.
The evidence was based on complaints by party candidates and information from sources in the security services, he said.
Despite accusing the government of rigging the vote, Bhutto had rejected calls for a boycott, saying she did not want leave the field open for Musharraf's loyalists.
Since Bhutto's slaying, the government has come under harsh criticism for its security arrangements for her, its claim that an Islamic militant was behind her death and its conclusion that it was the force of the blast and not gunshot wounds that killed her.
Her husband, Asif Ali Zardari, has led calls for an international, independent investigation into the attack.
The government rejected this, but said in a statement that its own investigation would be thorough and transparent and "will not shy away from receiving assistance from outside, if needed."
U.S. officials said the United States had quietly joined calls for international experts to join the probe and expected investigators from Britain's Scotland Yard to play a significant role.
As part of the investigation, the government took out newspaper ads offering a 162,000 reward for information about her killers. The ad shows a fuzzy still frame from a video featuring the presumed shooter and bomber seconds before the attack, and a photograph of the bomber's severed head.
Officials said the U.S. provided aabout threats against her before the former Pakistani prime minister was assassinated.
They said American spy agencies advised Bhutto's aides on how to boost security, although key suggestions appear to have gone unheeded.