The film-maker Alfonso Cuarón, riding high after winning this year's best director Oscar, has launched into political activism in his Mexican homeland by throwing down the gauntlet to the president.

The London-based director of Gravity published a full-page advertisement in Mexican newspapers on Monday addressed to President Enrique Peña Nieto and demanding answers to 10 questions about the country's controversial energy reform.

Cuarón explains his advertisement as a response to an interview the president gave two months ago dismissing the director's earlier low-key public expressions of opposition to the reforms as the result of ignorance about its benefits for the nation.

"I am not informed because the government you head has not shared with me – with us Mexicans in general – the indispensable things we need to understand it," Cuarón writes, before listing his questions. "I await your response, alongside many Mexicans," he finishes.

The constitutional reform, approved by the national legislature last year with little substantial debate, though much drama – including a deputy stripping at the podium – foresees a dramatic opening up of Mexico's state-owned energy sector to private-sector participation. The government's legislative proposals to define what this will mean in practice are already overdue.

Cuarón's questions include a demand for outlining when exactly the government's promises of falling energy prices will be reflected in household bills, as well as details of measures to protect the environment from the potential impacts of a production boom rooted in concessions negotiated by powerful multinational companies.

"In a country, like ours, where the rule of law is so weak (and often absent), how can the phenomenon of large-scale corruption be avoided?" he asks in another of the questions.

Peña Nieto responded to Cuarón's letter with three tweets on Monday afternoon that welcomed the questions he said "will help understanding of the reform's reaches and benefits". Eschewing the personal nature of the director's challenge, the president added that the government would answer them all once it had presented the secondary energy legislation.

While Mexican cultural names regularly feature within lists of public figures endorsing political, social and environmental causes, it is rare for individual personalities to launch such direct challenges.

Cuarón's paid advertisement, accompanied by a website www.diezpreguntas.com where the letter is translated into English, German, French and Italian and a Twitter account, produced an immediate impact within Mexico.

The twitter hashtag #Cuarón was soon a national trending topic, while the letter was reported prominently on mainstream news websites.

"Cuarón is difficult to dismiss because he is obviously independent, successful, and obviously acting with no hint of social resentment and only concern about what is happening in Mexico," Sergio Aguayo, an analyst, said on MVS Radio. "It boils down to asking who will benefit and who suffer from such an important reform."