Embattled stem cell researcher Haruko Obokata submitted additional documents to the state-backed Riken Institute on Sunday to back up her denials of alleged misconduct in her research methods, and called for more time to prepare evidence, her lawyer said Monday.

The documents, emailed to Riken by one of her lawyers, Hideo Miki, asked Riken to suspend its investigative committee's review for two weeks, citing her "poor health" and other reasons.

"(Obokata) is in the hospital now due to poor health and (she and her lawyers) are not able to have a long meeting. We need substantial time to conduct fulfilling hearings (with Obokata)," the documents said.