Miliband is set to make a case for progressive change only being possible inside a reformed EU, while accusing pro-Brexit campaigners of wanting to usher in a "free-market, low-regulated, race-to-the-bottom offshore Britain".
As the referendum campaign gets firmly into its last 100 days, Miliband will try to garner Labour support for In, claiming that leaving the EU will hurt Labour policies.
Read more: Donald Trump says "Britain may leave the EU"
"I want to send a very clear message to the nine million people who voted Labour at the last election: I believe the change you voted for, and still want to see in Britain, can only be achieved by us remaining in the European Union," he will say.
"And I believe that leaving would irreparably set back the cause of Labour politics."
And turning his attention to the Conservative party, he will caution that the referendum is too important to be dominated with discussion about Tory factionalism.
"The civil war in the Conservative Party cannot and must not obscure the central question in this referendum: are we more likely to secure social justice and progressive change inside the EU or outside? The answer is resoundingly that we should vote to remain," he will add.
His intervention comes as US presidential hopeful Donald Trump said that the UK could leave to vote the EU "based on what he is hearing".
It also coincides with the a Moody's report that said that the economic costs of Brexit would outweigh the potential benefits, with the UK leaving the EU leading to heightened uncertainty, weaker medium-term growth and a downturn in investment.