MEXICO CITY, March 8 (Reuters) - Leftist Andres Manuel Lopez Obrador leads by 13.6 percentage points in the run-up to Mexico's July 1 presidential election and has an even bigger advantage over the ruling party candidate, a voter survey by polling firm Ipsos showed on Thursday. The opinion poll seen by Reuters showed two-time runner-up Lopez Obrador, a former mayor of Mexico City, garnering 36.3 per cent support in the election. Running second on 22.7 per cent was Ricardo Anaya, a onetime leader of the centre-right National Action Party (PAN), who fronts the challenge of a right-left coalition. Back in third, on 15.1 per cent, was former finance minister Jose Antonio Meade, the candidate of President Enrique Pena Nieto's Institutional Revolutionary Party, or PRI. The Ipsos survey is the latest of several opinion polls to show Lopez Obrador in a strong position ahead of the start of formal campaigning on March 30. He finished second in 2006 and 2012. The 64-year-old founder of the National Regeneration Movement (MORENA) party has capitalised on disaffection with the PRI over a slew of political corruption scandals, increasing gang violence and sluggish economic growth. Meade, who is not formally affiliated to any party, has so far struggled to gain traction in a race being run in the shadow of strained relations between his government and US President Donald Trump, who has frequently criticised Mexico. The poll was the first conducted by Ipsos since the three main contenders were formally chosen as candidates last month.