The tourists have been shaken since the attack on former Prime Minister Benazir Bhutto's motorcade and team manager Logan Naidoo told reporters that a final decision on playing in Karachi would be made in the next few days.
"We are monitoring the security situation in the country on a day-to-day basis. We are waiting for feedback on the situation in Karachi from high-level Pakistani officials after which we will make a decision," Naidoo said on Sunday.
The South Africans had discussed abandoning the tour on Friday but agreed to continue after assurances from top level security officials and the Pakistan Cricket Board (PCB).
South African skipper Graeme Smith said the security situation was obviously at the back of the minds of the players.
"The thing is we have to manage on a daily basis and rely on our security guys to give us feedback," Smith said.
After splitting the first two one-dayers in Lahore, the teams will play the third match of the series in Faisalabad on Tuesday and the fourth in Multan on Friday.
The final one-dayer is scheduled for Oct. 29.
A PCB official said the board would allow the South Africans to make their own decision on the Karachi contest.
"We know they are not comfortable about playing in Karachi after the tragedy. We will give them briefing soon. We have discussed other options with them including playing the final match in Multan or Lahore," he told Reuters, while declining to be named.