Jeremy Corbyn has urged Sir Keir Starmer to join striking workers on picket lines telling him to "listen to what people have to say".
The former Labour leader said those taking industrial action felt they had no other option and should be respected for their decision.
The Islington North MP criticised his replacement for ordering his shadow cabinet not to join workers who had walked out.
The former Labour leader said you 'learn a lot' from joining a picket line
James Manning
Starmer told his top team last year that the party needed to act like a "government in waiting" and should not join those on picket lines as they would be unable to do so if in power.
Corbyn said last night: "You find out a lot on a picket line because those are people who are making a sacrifice.
"They don't want to lose wages but they go on strike because they feel they have no alternative."
Strike action has been taken en masse in recent weeks, with rail workers, postal workers and those working in healthcare all walking out.
Next month 10,000 civil servants are also set to stage a walk out and teachers are also being balloted on walking out.
Workers are demanding higher pay and working conditions.
Corbyn claimed Starmer would better understand the disputes if he went and joined those taking action.
"Go along and listen to what people have to say, you learn a lot from it," he told ITV.
"I've stood and had quite long discussions with postal workers about the stress levels they face. They feel under valued.
Jeremy Corbyn said workers feel under valued
Lucy North
"They're part of our communities, they deliver our post, they deliver our packages and they feel they are just being turned into a gig economy.
"And so these disputes, and the rail workers also, they're not just about pay. They're about valuing and recognising the skill levels of people in all those areas."
Starmer has sought to radically overhaul the Labour Party since taking on the job as leader in April 2020.
In his new year message he claimed he'd had "restored a degree of trust" in the party among the British public.
He said: "In 2022 they looked at us again and I felt, for the first time in a while, we could return their gaze with confidence."
The Holborn and St Pancras MP added: "We can feel the public looking at us again – and we won’t let up.
"We’ll work every day to earn their trust. Show them a new way of governing. And lead them to the fairer, greener, more dynamic Britain where aspiration is rewarded, working people succeed, communities control their own destiny, and where politics doesn’t hide from the big challenges that face our children."
