March 25 (Reuters) - Chilean miner SQM's board chairman

challenged what he called the questionable motives of the

company's major shareholder, China's Tianqi Lithium Corp, the

latest jab in an increasingly public spat over SQM's planned

partnership with state copper producer Codelco.

Tianqi, a global lithium rival that holds about 20% of SQM

shares, last week raised concerns over transparency in the talks

with Codelco, which is slated to take a 50% plus one share stake

in the new joint venture beginning in 2025 under a government

policy aimed at boosting state control in Chile's lithium

industry.

SQM, the world's No. 2 lithium producer, and Codelco reached

an initial agreement in December and aim to finalize details by

May 31.

Tianqi Chief Executive Frank Ha emphasized the company's

worries over the Codelco deal in comments to Chilean newspaper

La Tercera published Saturday.

When asked if Tianqi would be interested in bidding for its

own contract to exploit lithium from Chile's Atacama salt flat,

in the case that SQM's deal with Codelco in the area were to

fall through, Ha said Tianqi would be open to "all opportunities

that align with the company's strategic vision."

SQM Board Chairman Gonzalo Guerrero singled out the remark

in a statement distributed by SQM, arguing that it "raises

questions about Tianqi's real objectives" just as negotiations

with Codelco are close to concluding.

"Are these statements in the best interest of SQM, or

Tianqi?"

Tianqi did not immediately respond to a request for comment.

Guerrero also rejected Tianqi's urging to put the Codelco

deal to a shareholders' vote, which he said could potentially

give Tianqi veto power.

"It's worth asking, once the transaction is vetoed, whether

Tianqi would try to pursue this business opportunity for

itself," he said.

Tianqi acquired a near-quarter share of SQM in 2018 for $4.1

billion amid concerns from regulators, competitors and consumer

groups that the deal could give Tianqi a near monopoly over the

global lithium market.