South Africa will send a top security consultant to Karachi to decide whether it is safe to play the fifth and final one-day international there next week.
Pakistani officials said South Africa were uncertain about going ahead with the game following Friday's assassination attempt on former Prime Minister Benazir Bhutto, which killed 139 of her supporters.
At least one suicide bomber attacked Bhutto, who was returning from eight years of self-imposed exile, as she rode in a truck through streets packed with hundreds of thousands of people welcoming her home.
"The South African security consultant will go and check the situation there for himself and report back on Wednesday, after which the South Africans will take a decision on the venue for the final match," Pakistan Cricket Board (PCB) spokesman Ehsan Malik said on Tuesday.
Both countries have discussed shifting the game to Lahore, although Pakistan expressed concern about the impact a change in venue would have on future tours to the country.
"If the match is shifted we are concerned it could have adverse effects for tours by other teams in the coming months," said Shafqat Naghmi of the PCB.