Communications Minister Mohamed Said said on Sunday that the death toll of 23 foreigners and Algerians from an Islamist attack on a gas complex in the Sahara desert may rise.
"I fear that it may be revised upward," Said told public Channel 3 radio, as several countries indicated they had citizens still missing after the deadly siege of the In Amenas complex ended in a bloodbath on Saturday.
Algerians have not yet given details of the foreigners killed, leaving it to their home countries to elaborate.
Japan has reported that 10 of its citizens are still missing, as are five Norwegians and two Malaysians.
At least one Algerian was killed in the four-day siege, according to official sources.
The bloody siege to the In Amenas gas complex ended on Saturday when Algerian special forces stormed the remote desert installation.
Islamist militants had raided the complex on Wednesday and by Thursday most hostages had been freed when forces launched a first rescue operation.
World leaders led by US President Barack Obama and his French counterpart Francois Hollande have laid responsibility for the deaths with the Islamist "terrorists."