The central bank expects to launch the scheme by the end of this year, and will release a preliminary outline of the scheme at its next policy-setting meeting in July.
As widely expected, the central bank maintained its yield curve control targets set at -0.1% for short-term interest rates and at around 0% for 10-year bond yields.
It also extended by six months the September deadline for its pandemic-relief programme.
The BOJ last year ramped up purchases of commercial paper and corporate bonds, and put in place a loan programme aimed at channeling money to cash-strapped smaller firms, to cushion the blow from the pandemic.
(Reporting by Leika Kihara, Tetsushi Kajimoto and Daniel Leussink)