Elliott, which owns $1.5 billion worth of shares in three Hyundai group companies, called for a committee to review its proposals with other investors and experts, and said its attempts to discuss a new plan had been met with silence.

Hyundai rejected the committee idea and added that it hoped "to share our thoughts on how to improve shareholder value with all of our shareholders in due course".

A person close to Hyundai Motor Group told Reuters "it's difficult for Hyundai to accept Elliott's proposal, as it primarily benefits Hyundai Motor".

He said the company is listening to various opinions to come up with a new proposal, but no decision had been made.

In a rare victory for an activist shareholder in South Korea, Elliott and other shareholders in May forced Hyundai to scrap its own restructuring plan which would have prepared the group for a switch of management from father to son.

The setback for Hyundai, the country's second-largest business group, came amid growing public scrutiny of families controlling large conglomerates in South Korea after a corruption scandal involving the Samsung Group last year.

Hyundai said in May that it would "supplement and improve" the plan, which it said aimed to address a government call for the company to streamline its ownership structure.

Hyundai has yet to make its revised plan public.

"We express our frustration as to HMC board's silence towards our consistent attempts... to communicate and advance the restructuring and other projects," Elliott said in a letter sent to Hyundai on August 14.

The letter, made public on Friday, proposed a committee to discuss restructuring, shareholder returns and a board makeup.

Hyundai rejected the proposal for the committee, saying it could violate "fair disclosure rules, which prevent us from sharing material confidential information about the company and its businesses to only a subset of our shareholders."

The renewed pressure comes as Hyundai seeks to focus on operational issues after its quarterly profit halved to an almost six-year low, and South Korea's trade tensions with the United States threaten to disrupt the firm's production plans.

INVESTOR INTEREST

The latest proposals from the hedge fund controlled by billionaire Paul Singer call for auto-parts maker Hyundai Mobis Co to sell its after-sale service business to Hyundai Motor Co, and then merge what is left of Mobis with logistics affiliate Hyundai Glovis Co.

Then it proposed the merged Mobis-Glovis buy stakes in Hyundai Motor from the controlling family and affiliate Kia Motors to tighten its grip over the crown jewel of the group. The founding family would increase their stake in the combined Mobis-Glovis by purchasing Kia's shares in the company.

Elliott also recommended changes to the board to improve governance and enhance shareholder returns.

The plan to sell Mobis' profitable after-sales business to Hyundai Motor could draw opposition from Mobis shareholders, and increase regulatory risks, analysts said.

Yet the news raised investors' expectations that the stalled restructuring of Hyundai may revive, sending shares in Hyundai Glovis 5.1 percent higher and Hyundai Mobis up 2.4 percent. Shares in Hyundai Motor fell 1 percent.

"It seems Elliott wants to rekindle investor interest in restructuring as Hyundai has been silent since it withdrew its plan," said Park Sang-in, a professor at Seoul National University and expert on chaebol reform.

He said Elliott may have made the proposals to pressure Hyundai for concessions, such as higher shareholder returns and a buyout of Elliott's stakes.

Hyundai's original plan was to spin off Hyundai Mobis' lucrative after-sales business and merge it with Hyundai Glovis, whose top shareholders are chairman Chung Mong-koo and his only son and heir apparent, Chung Eui-sun.

Elliott owns around 3.0 percent of Hyundai Motor, 2.1 percent of Kia Motors and 2.6 percent of Mobis.

(Reporting by Hyunjoo Jin in Seoul and Liana B. Baker in New York; Additional reporting by Ankit Ajmera in Bengaluru and Heekyong Yang in SEOUL; Editing by Miyoung Kim and Darren Schuettler)

By Hyunjoo Jin and Liana B. Baker