The UNHCR said in a joint statement with the International Organization for Migration that if the death toll was confirmed, it would be the biggest loss of life so far this year.
The alert was raised on Wednesday when fishermen rescued six of the migrants. A fishing community in Aceh said they had been standing on the hull of the boat after it capsized due to high tides.
For years, Rohingya have left Buddhist-majority Myanmar where they are generally regarded as foreign interlopers from South Asia, denied citizenship and subjected to abuse.
More than 2,300 Rohingya arrived in Indonesia last year, UNHCR data showed, surpassing the number of arrivals in the previous four years combined.
The 2023 toll of at least 569 Rohingya dead or missing while trying to flee Myanmar or Bangladesh was the highest since 2014, the UNHCR said in January.
Babar Baloch, a UNHCR Asia spokesperson, told Reuters on Friday there had been 151 people on this latest boat, some 75 of whom have been evacuated by local authorities, while the rest were "presumed dead or missing".
Faisal Rahman, UNHCR's protection associate in Aceh, told Reuters the surviving Rohingya were in a good condition and were staying at a Red Cross building in West Aceh.
The immigration agency in Aceh did not respond to a request for comment.
