TOKYO, March 27 (Reuters) - Former Japanese finance ministry official Nobuhisa Sagawa said on Tuesday that there were no instructions from Prime Minister Shinzo Abe, his wife, Finance Minister Taro Aso or their top aides to alter documents about a murky land deal at the heart of a suspected cronyism scandal.

Sagawa is testifying in parliament under oath over the case.

The suspected scandal and cover-up have slashed Abe's support rates and clouded his chances of a third term as ruling Liberal Democratic Party (LDP) leader in a September party vote.

The finance ministry admitted on March 12 that it had altered documents about a heavily discounted sale of state-owned land to school operator Moritomo Gakuen, which had ties to Abe's wife, Akie. Sagawa, who resigned as National Tax Agency chief this month, was formerly head of the finance ministry division in charge of the documents. (Reporting by Linda Sieg and Kiyoshi Takenaka Editing by Chang-Ran Kim)