The majority of supporters of the hard-left French presidential candidate Jean-Luc Mélenchon will abstain or spoil their ballot papers in Sunday’s second round, according to the results of a consultation of members of his France Unbowed movement.

About 450,000 of his supporters were asked to say whether they would abstain, spoil their ballots or support Emmanuel Macron in the second round runoff this Sunday. Voting for the other candidate, the Front National’s Marine Le Pen, was not an option.

The results, released on Tuesday afternoon, showed that of more than 243,000 Mélenchon supporters who responded, 87,818 (36.1%) intended to spoil their vote, 84,682 (34.8%) planned to support Macron and 70,628 (29%) would not turn out for the second round. The figures suggest a total of 65% will not vote for Macron.

Mélenchon, who came fourth in the first round vote 10 days ago with the support of 19.5% – about 7 million voters – has been heavily criticised for not advising his supporters how to vote.

Both he and his team have, however, insisted not a single vote should go to Le Pen. Alexis Corbière, Mélenchon’s spokesman, said they were not going to take “moral lessons” on how to combat the far-right Front National, and Mélenchon was not a “guru”.

On YouTube last Friday, Mélenchon said he would have been in the second round “but for 620,000 votes”. He told supporters: “I’m going to vote, but what I’m going to vote, I’m not going to say. You don’t have to be a great scholar to guess what I’m going to do.” He added: “Is there a single person among you who doubts the fact that I’m not going to vote for the Front National? Everyone knows that.”

Mélenchon made it clear he did not support Macron’s programme. Macron is still favourite to win Sunday’s presidential vote, but opinion polls suggest the gap with Le Pen is narrowing.