Bulgarian Agriculture Minister Rumen Porozhanov has resigned from office amid a corruption investigation into the possible misuse of EU development aid.

Porozhanov is the latest in a line of high-profile ministers to resign over reported real estate scandals in what Transparency International found to be the EU's most corrupt state in its 2018 index.

Top Bulgarian officials have been found to be buying luxury real estate far below market prices, and a recent investigation was launched into the possible fraudulent use of development aid from the EU.

The investigation is specifically focusing on whether EU funds were used by Bulgaria's State Fund Agriculture department to build hundreds of private guesthouses.

One executive of the department resigned at the beginning of the month after her phone number was discovered on the website of one of the properties.

Porozhanov's resignation came just a fortnight after the fraud investigation was launched, but he has denied any wrongdoing.

According to local media quoting a government statement, Porozhanov chose to resign so as not to affect the working government.

He said: "I think I have made every effort to work successfully in one of the largest ministries."

"There are a lot of problems in the sector and certainly not all of them are solved, but everyone has been trying to find a balanced and fair solution."

The EU Commission has repeatedly criticised Bulgaria in the past for failing to prosecute its allegedly corrupt politicians.

In March, the country's second most powerful politician Tsvetan Tsvetanov resigned amid the same unfolding scandal after it was found that he had purchased a luxury apartment in the capital, Sofia, for almost a quarter of the market price.