This is what could be an attempt to speed up a takeover battle that has been waylaid by delays.
Bidvest, a conglomerate that spans shipping to auto sales, is attempting to thwart a takeover of Adcock by Chilean firm CFR Pharmaceuticals.
CFR has bid 12.8 billion rand in cash and shares for Adcock, an offer that shareholders were initially due to vote on last year, but which has since been delayed twice and is now expected in mid-February.
"Adcock has been subjected to a protracted period of continuous delays throughout which time the attention of the Adcock board and management has been diverted from optimising the operational performance," Bidvest said in a statement.
"This has been exacerbated by the protracted process relating to the offer by CFR Pharmaceuticals."
Bidvest said its cash offer for 34.5 per cent of Adcock will close at 1500 GMT on February 4.
Shares of Adcock were little changed, as were shares of Bidvest.