López Obrador, who has consistently ranked in the lead in major polls, has 50% of voter support, 26 percentage points ahead of his nearest rival, according to the poll published in newspaper El Financiero.

The former Mexico City mayor’s support rose from 46% in a May survey by the same pollster.

López Obrador has promised to run an austere government and to combat corruption, aiming to contrast with the deeply unpopular ruling Institutional Revolutionary Party (PRI), which has held power for most of the past nine decades.

Right-left coalition leader Ricardo Anaya followed in second place, dropping 2 percentage points to take 24% of voter support, Monday’s poll showed.

The PRI’s José Antonio Meade, a former finance minister, remained in third place but increased two percentage points to 22%.

Jaime Rodríguez, the only independent candidate since former first lady Margarita Zavala dropped out of the race last month, lagged far behind with 4% of voter support.

El Financiero said it conducted face-to-face interviews with 1,201 people between May 24 and 28, registering a margin of error of 2.8 percentage points.

The survey found that López Obrador, 64, now making his third presidential bid, was stronger than other candidates in addressing corruption, a major election theme. He ranked weakest in addressing Mexicans’ concerns about security compared with his rivals.

More than half of voters who said they would support López Obrador said they were “very convinced” they would cast ballots in his favour, the poll also said.

The most recent major voter poll, published last Thursday by polling firm Parametria, produced similar results, giving López Obrador a 25-percentage point lead over Anaya.