SANTIAGO, Dec 14 (Reuters) - Codelco Chairman Maximo Pacheco affirmed on Thursday his prediction that Chile's state-owned copper giant will reach an agreement with lithium miner SQM this year.

Codelco, the world's largest copper producer, has been negotiating a partnership with Santiago-based SQM since mid-year. Codelco was tasked by President Gabriel Boric in April to lead the government's plan to take state control over strategic lithium projects.

"I maintain it," Pacheco told Reuters when asked about his September forecast of reaching a deal this year, adding that due to legal and regulatory issues he could not elaborate.

"This is a negotiation that is very delicate, sensitive and that affects securities that are traded on the stock market," Pacheco said. "I can't give you any details."

The negotiations have been kept strictly confidential. SQM has said it would not comment publicly until the final deal is signed or negotiations are terminated.

Codelco has no experience extracting lithium, which is in high demand for making electric vehicle batteries, and production in Chile has dipped partly due to delays in multibillion-dollar projects and other operational issues.

In October, Codelco agreed to acquire Australia's Lithium Power International for about $244 million.

(Report by Fabián Andrés Cambero and Alexander Villegas; Editing by Richard Chang)