UPDATE 1-Elliott wants Hyundai Motor Group to adopt holding company structure

* Says steps proposed by Hyundai Motor Group not enough

* Wants treasury shares canceled, independent board members added (Add details from Elliott's statement)

SEOUL, April 23 (Reuters) - U.S. activist hedge fund Elliott Management said on Monday a restructuring plan proposed by Hyundai Motor Group to simplify its shareholding structure was not enough, and recommended it create a holding company, among other measures.

Earlier this month, Elliott disclosed that it holds more than $1 billion worth of shares in three key affiliates of Hyundai Motor Group and called for a "more detailed roadmap" as to how the group will improve corporate governance, optimize balance sheets and enhance capital returns.

The three affiliates are Hyundai Mobis, Hyundai Motor Co and Kia Motors.

The giant autos-to-steel group last month announced a plan to streamline its ownership structure, responding to calls from the government and investors for greater transparency and better governance at family-controlled conglomerates, or chaebols.

"Elliott is encouraged that the Group has acknowledged the need for an improved ownership structure. However, the unwinding of the current circular shareholding by itself...lacks clear benefits to minority shareholders," Elliott said in a statement.

Other steps it proposed included canceling treasury shares and adding more independent board members.

A Hyundai Motor Co spokeswoman did not have an immediate comment.

It is Elliott's latest challenge to South Korea's family-run conglomerates after it forced Samsung Electronics Co Ltd to increase shareholder returns in 2017, and comes amid a government campaign to boost investors' power in a country where shareholder activism is rare. (Reporting by Hyunjoo Jin, Additional reporting by Ju-min Park; Editing by Muralikumar Anantharaman)