The Brazilian department of justice has ordered BNDES, the country’s development bank, to disclose its loan contracts relating to the US$682mn financing of the Mariel port development in Cuba.

A release on the department’s website references “strong signs of irregularities” to justify the forced disclosure, which BNDES opposed once before, to no avail. The order is likely related to Brazil’s investigation into former president Luiz Inácio Lula da Silva’s links to construction giant Odebrecht, whose subsidiary Companhia de Obras e Infra-estrutura received the BNDES financing for the Mariel port development.

In 2015, Brazilian weekly Época published a report on Lula’s activities around the deal, implying that the former president had acted as lobbyist for Odebrecht, which was allegedly concerned about its ability to secure BNDES financing due to its existing levels of indebtedness.

The report included investigation documents showing that BNDES had offered “exceptional” conditions to Cuba for the loan, including the 25-year term instead of its regular 12-year tenors. More recently, in February this year, the magazine published a confidential government document in which investigators concluded that the former president had abused his influence to benefit Odebrecht.

The financing was disbursed in five instalments between 2009 and 2013, each with a tenor of 300 months, according to data from BNDES Transparente, an online platform set up by the bank in 2015 to improve transparency.

The port, which opened in January 2014 and is operated by Singaporean port operator PSA International, has replaced Havana as Cuba’s most important port.

Equipped for ships passing through the recently-expanded Panama Canal, it is seen as strategic for the development of trade to and from Cuba. The island’s relations with the US are improving, and a lifting of the US’ trade embargo has been mooted – though widely contested by American politicians and therefore practically unimaginable before the November 2016 presidential election.

Recently, concerns emerged in the Brazilian press that the port development had not delivered the anticipated increase in business for Brazilian companies. According to Antonio Zaccaria, then spokesman for Odebrecht, speaking at the port’s inauguration two and a half years ago, US$802mn in business for Brazilian companies was driven by the construction of the port, generating 153,000 jobs in Brazil, but the increase in Cuban business does not seem to have lasted past the construction phase.

Odebrecht’s chief executive Marcelo Odebrecht was arrested in June 2015 in connection with the massive corruption scandal focused on state-run oil company Petrobras.