SINGAPORE (Reuters) - Noble Group improved the terms of its controversial $3.4 billion debt restructuring deal and won the support of its biggest shareholder as the commodity trader seeks to complete the vital transaction.

Singapore-listed Noble's debt-for-equity swap has already won the backing of more than 83 percent of the holders of its senior debt but it also needs a majority of its shareholders to approve the restructuring.

"The revised structure granting shareholders 15 percent equity in New Noble has my full support," Noble founder Richard Elman said in Noble's statement on Monday. Elman resigned from the company's board last month, citing differences with creditors and the board.

Noble said Elman, who founded the company more than 30 years ago and holds nearly 18 percent of its shares, would be appointed as an executive director on the new company's board.

Noble says the debt-for-equity swap is crucial for its survival, after it sold billions of dollars of assets, took hefty writedowns and cut hundreds of jobs over the past three years.

Noble is seeking to halve its senior debt and in return hand over 70 percent of the restructured business to creditors, which are mainly made up hedge funds.

The company said all existing shareholders will get a 15 percent stake in the restructured firm, replacing a previous proposal under which they would receive 10 percent and an option for a further 7.5 percent subject to conditions.

The earlier proposal had been criticised by some shareholders.

Noble's Chairman Paul Brough said in the statement that the backing by Elman and the support from creditors "demonstrate that we are now firmly entering the last stage and seeing material progress in the delivery of the company's restructuring."

If Noble does not receive shareholder approval, it plans to file for administration in the United Kingdom and said that only those shareholders who voted for the first proposal would be allocated shares in the new company.

Some bondholders and shareholders such as Goldilocks, an Abu Dhabi Financial Group equity fund, and the Singapore Exchange have criticised the restructuring and Noble's restrictions on allocating shares to investors.

(Reporting by Anshuman Daga; Editing by Jacqueline Wong and Christian Schmollinger)

By Anshuman Daga