However the investment bank then expected to see "a rally to new highs over the next three-plus months", analyst Christopher LaFemina said.
China announced plans this month to sell some of its strategic reserves in a move designed to stabilise prices.
The first batch of sales would be via public auction in July and more sales were "highly likely", Jefferies said.
China's National Food and Strategic Reserves Administration said this week China would sell 20,000 tonnes of copper, 50,000t of aluminum and 30,000t of zinc on July 5-6.
LaFemina said these amounts equated to 0.16% of annual Chinese demand and 0.08% of global demand for copper, 0.14% and 0.08% respectively for aluminum and 0.45% and 0.22% for zinc.
He said while the magnitude of the announced sale of reserves was relatively small, combined with weaker underlying demand and seasonal factors it would not be surprising for these base metal prices to fall further.
However these were "temporary factors" and Jefferies would argue the longer-term positive outlook had not changed, he said.
"The longer-term positive fundamental outlook for these base metals is based on a combination of global cyclical demand growth following a deep recession in 1H20, secular demand growth due to the green energy transition and major supply constraints," LaFemina said.
He noted China last released copper from its strategic reserves in November 2005, when it sold 51,000t during a period of very strong demand.
"The copper price increased during that period and was 75% higher six months later," he said.
He said the country last sold aluminum and zinc in late 2010, with the former price rising sharply over the following six months and zinc slightly increasing.
China has 1.5-2 million tonnes of copper reserves, about 800,000t of aluminum reserves and less than 400,000t of zinc reserves, Jefferies said.
It would "be surprised" if the SRB were to sell more than 10% or 200,000t of its copper reserves.
It recommended buying shares in Freeport-McMoRan, First Quantum Minerals and Glencore.
