TOKYO, May 19 (Xinhua) -- Japan's education ministry has begun an internal probe into allegations that Prime Minister Shinzo Abe may have been complicit in a government plan to allow a heavily subsidized medical school to be opened at a university operated by his friend.

Education Minister Hirokazu Matsuno told a press briefing Friday that the education ministry has started to investigate documents presented by the opposition Democratic Party that may implicate the prime minister and the government.

He said that seven officials of the ministry's higher education bureau are being interviewed on the matter.

The controversy lies in the fact that Okayama University of Science was chosen by the government to open a veterinary medicine school in Ehime Prefecture, one of Japan's national strategic special economic zones, which has far more relaxed regulations to boost growth in the area as part of Abe's overall growth strategy.

The university is operated by Kake Educational Institution, which is headed by a close friend of Abe.

Democratic Party lawmaker Yuichiro Tamaki said at a Lower House committee meeting on Wednesday that an education ministry advisory panel was currently assessing an application to open the school and the ministry had prepared a document stating that the Cabinet Office said that Abe backs the plan.

Tamaki said the document suggested that the education ministry was told by the Cabinet Office that the choice for the new school "was heard to have been the prime minister's wish." Tamaki added that he is in possession of the document.

Matsuno maintained that neither Abe nor his office had given him instructions regarding the new school to be opened and Abe himself has also denied the allegations, stating that his friend has never consulted him regarding the plan to open the new department.

The Democratic Party maintains, however, that the document shows that negotiations had taken place between the ministry and the Cabinet Office regarding the timeframe for opening the new department at the university.

The latest claim follows Abe, his wife and other ministers being embroiled in an as yet unresolved cut-price state land deal with another private school operator in Osaka.

Moritomo Gakuen, the operator of a nationalist school in Osaka, said it had received a donation and the backing of Abe to open a new school on a piece of land owned by the government and sold to the operator for just a fraction of its appraisal value.