SANTIAGO, June 5 (Reuters) - Chile's financial regulator said on Wednesday it is aiming to respond as quickly as possible to a complaint from China's Tianqi Lithium over a planned lithium partnership between miner SQM and Chilean state miner Codelco.

Tianqi, which holds about a fifth of shares in SQM, has argued to the regulator that a shareholders' vote is needed to approve the agreement. The deal would give Codelco a majority stake of SQM's lithium operations in Chile's Atacama salt flat.

SQM and Codelco announced the final terms last week but said certain conditions still needed to be met, including a rejection of Tianqi's proposal by Chile's Financial Market Commission (CMF).

SQM has maintained that only a board vote is required, citing an earlier CMF determination.

Asked about the matter in a Senate hearing, the regulator's President Solange Bernstein said the commission was aiming to work quickly. It received Tianqi's appeal in May and requested a response from SQM by Monday.

"We are going to take a while to be able to resolve it, but we're going to do it as quickly as possible," she said.

"We have to analyze the details of the agreement, as well as SQM's response."

The commission's legal director, Jose Antonio Gaspar, said Tianqi could appeal the CMF decision to a court.

Tianqi said in a filing on Sunday with the Shenzhen Stock Exchange it may consider further action to protect its interests. (Reporting by Fabian Cambero; Writing by Daina Beth Solomon; Editing by Alexander Villegas and Richard Chang)