A $1.2 billion disbursement is expected in August after the IMF’s management gives final approval, the source said, asking not to be identified before a formal announcement.
Representatives for the IMF in Pakistan and the nation’s finance ministry did not reply to emails seeking comment.
The disbursal would offer relief to the South Asian nation, whose foreign-exchange reserves can cover less than two months of imports. Inflation has accelerated to a 13-year-high.
Pakistan has raised electricity tariffs and almost doubled diesel pump prices over the past two months to meet the IMF's conditions.
The Washington-based lender has also agreed to increase the loan programme size by $1bn — taking it to a total $7bn — and extend it through June 2023, the source said.