MEXICO CITY — Mexico’s landmark anti-corruption drive, inaugurated by President Enrique Peña Nieto under intense pressure to answer the scandals jolting his administration, is being blocked by the government’s refusal to cooperate on some of the biggest cases facing the nation, according to members of the commission coordinating the effort.

Attempts to look into the use of government surveillance technology against civilians, the embezzlement of tens of millions of dollars through public universities and allegations of widespread bribery to win construction contracts have all been thwarted, commission members say.

Marred by scandals that have embroiled his administration, his allies and even his own family, Mr. Peña Nieto agreed to the creation of a broad anti-corruption system last year that was enshrined in the Constitution, a watershed moment in Mexico.

But after nine months of pushing to examine the kind of corruption that ignited public outrage and brought the new watchdog into existence, some of its most prominent members say they have been stymied every step of the way, unable to make the most basic headway.