Labour’s ruling body plans to weaken the power of MPs by scrapping their right to veto candidates for a leadership contest, according to Ken Livingstone.

The former London Mayor, a key Corbyn supporter, said Labour’s national executive committee (NEC) would consider plans to cut the threshold of MP nominations necessary for a candidate to make it on to the ballot paper.

The change would make it easier for a left-wing MP to qualify as a candidate in the event of another leadership election. Jeremy Corbyn only mustered the 35 nominations required to make it on the ballot paper at the last minute after some MPs “lent” him their support in an attempt to broaden the debate, even though they actually voted for other candidates.

A rule change would remove the need for a leadership contender to win the backing of 35 MPs.

“The idea of Labour MPs having a veto over who stands is nonsense,” Livingstone said.

“The Labour party before Blair was a genuinely open, democratic one. Jeremy’s bringing that back. Exactly how isn’t going to be resolved til the annual conference. But that’s what we want back.”

Livingstone suggested the new rules could require a candidate to find just two MP supporters – a proposer and a seconder – and, in the New Statesman interview, appeared to go further when he said: “Why not allow councillors to do it, and things like that?”

His intervention shows the left of the party is making contingency plans should Corbyn not survive as leader until 2020 – although it is highly likely the “moderates” in the Parliamentary Labour Party would resist such a reform.

Livingstone claimed any such reform would show the Corbyn era is different to that of the Blair years, adding: “Jeremy is genuinely a democrat. Unlike the New Labour regime, which was more like North Korea, internally.”

A spokeswoman for the party said: “There are currently no plans to change the rules for a leadership election. Rule changes are a matter for Annual Conference.”