The election commission is to announce its decision Wednesday on whether to hold the polls as scheduled but the Pakistan Dawn newspaper reported a 10-week to 12-week delay is likely.
The BBC said commission spokesman Kanwar Dilshad said keeping the Jan. 8 schedule "looks impossible."
The country's main opposition parties -- the late Bhutto's Pakistan People's Party and the Pakistan Muslim League-N led by former Premier Nawaz Sharif -- have said they do not want any postponement of the polls.
The United States also wants the elections to proceed as scheduled if they can be held in a "safe and secure way."
Dawn quoted official sources who said several election records have been destroyed in protests over the death of the former prime minister and that their recompilation, as well as redeployment of around 1 million temporary polling staff, would require 10 to 12 weeks.
There are also law and order concerns in some areas. Transportation and logistics problems have been aggravated by the suspension of oil supply and closure of gasoline stations, the report said.