The EU’s green deal to restore biodiversity, clean the continent’s soil, air and water, and mitigate climate breakdown is at high risk of being killed off, the co-president of the Green group of MEPs has warned.

The Belgian MEP Philippe Lamberts said the green deal, which has informed everything from tax policy to environment law making, would be a thing of the past if the far right made significant gains in the June EU parliamentary elections.

“The likelihood of [the far right and right] killing the green deal is very high. I mean, they make no mystery that after winning the ideological battle on asylum and migration their next target is the European green deal, and what they call the ‘woke’ economy.”

He said the Greens needed “to play their best game ever” – appealing to voters to make the right choice rather than believe the “absolute bullshit” of politicians who claim to be fighting to save the planet but do the opposite – to try to defeat the far right.

In the run-up to the elections, the EU has watered down a series of proposed laws including the nature restoration law (NRL), which is on the verge of collapse, and scrapped other plans including new rules on pesticides.

Lamberts praised the European Commission president, Ursula von der Leyen, for her continuing commitment to the green deal but reserved his sharpest criticism for the French president, Emmanuel Macron, who he said had lurched further to the right to see off Marine Le Pen and Jordan Bardella, the president of her Rassemblement National party.

By adopting positions that “mimic the language and the policies advocated by the far right … Bardella is just raising in the opinion polls”, said Lamberts. “He doesn’t need to do anything as Macron is doing his job [for him].”

Before his last session in the parliament on Wednesday, he railed against centrist politicians who appeased the right for their own electoral survival.

“I am angry, yes I am angry … here are some of the facts: soil, air, water are highly polluted in Europe, so much so, that actually you can’t even have bottled water that is clean,” he said.

The NRL, which aims to regenerate soil and water quality, was a case in point, he said. It was approved by parliament earlier this year and had the qualified majority to get it on to the statute books at an EU leaders’ summit in March.

But three days later, that slim majority fell apart after Hungary indicated it had changed its mind and joined seven other countries that either opposed or abstained, including Sweden, the Netherlands and Italy.

Sources in the Belgian presidency say they will fight to the end of their six-month term, on 30 June, to try to persuade Hungary or one of the other seven to change their mind.

But they admit it is on life support: “The best-case scenario is it is delayed,” said one source. “It will be unlikely to get through under Hungary,” they added. Hungary will take over the EU presidency from June until December.

“Then it would be up to the Danish [who take over the EU presidency in January]. But the worst-case scenario is that it falls completely and if the far right do well in the elections that is what we are looking at,” said a European parliament source.

The parliament is holding its last plenary session in Strasbourg this week before the 705 MEPs head back to their home nations for the election campaigns.

Lamberts, who is standing down after 15 years, said he would back von der Leyen for a second term as European Commission president, even though her Christian Democratic Union party belongs to the conservative centre-right group of parties in the EU, known as the European People’s party (EPP).

“Without her, there would have been no green deal. Let’s not kid ourselves. And I don’t see a second EPP politician that has the guts to carry on, let alone to start anew,” he said.

He suggested the former Italian prime minister Mario Draghi was the only other person with vision and enough personal gumption to fight off the populists. “I would love a combination of Draghi leading the council and von der Leyen leading the commission,” he said.