A 500-page report, published in November, detailed the kingdom's response to a Shiite uprising early this year. It concluded state security forces used "excessive and unnecessary lethal force."
At least 40 people died during the uprising and the United Nations had said it believed people were being tortured in state hospitals amid the crackdown.
The ICRC said it signed a memorandum of understanding with Bahrain's Interior Ministry that would give it access to detainees still held in the country.
"This agreement will allow ICRC delegates to visit all detainees in all places of detention under the responsibility of the Ministry of the Interior," Gerard Peytrignet, the head of the ICRC regional delegation in Kuwait, said in a statement.
Peytrignet said the purpose of the visits would be to assess the conditions of the facilities where detainees are held. He said his agency reached out to Bahrain when violence erupted in February.
A human rights official told al-Jazeera that police in Bahrain fired rubber bullets at protesters during ceremonies this week marking the Shiite holy day of Ashura. There were "a lot" of injuries, said one official.