SINGAPORE (Reuters) - Noble Group Ltd share price rose 4 per cent on Friday to its highest in more than a week, as the company vowed more transparency in the wake of reports by an obscure research firm accusing it of improper accounting practices.

Noble shares rose to as high as $1.045, extending gains from a one-year low of $0.92 hit earlier this week. The stock was the best performer on Singapore's benchmark Straits Times Index in early trading on Friday.

The research firm, Iceberg Research, said in its latest statement that it expects to see more writedowns on Noble's investment in Yancoal Australia.