Mr Corbyn's leadership rival Owen Smith has warned the British Labour party could "bust apart and disappear"
Jeremy Corbyn said no British Labour MP would dream of leaving the "family" that put them in parliament, in an attack on rebels.
Dismissing the idea of a party split in a scathing response after setting out his 10-policy leadership vision, Mr Corbyn suggested Labour MPs who quit would be betraying the people who voted for them.
When questioned after a speech in Dagenham about the suggestions Labour rebels could quit and form a new party if he was re-elected as leader, Mr Corbyn said: "I'm sure no Labour MP would even dream of walking away from the family of the Labour Party.
"The family of the Labour Party that helped to put them into Parliament in order to represent Labour views and Labour values."
It came after Mr Corbyn's leadership rival Owen Smith warned the Labour party could "bust apart and disappear".
He has made the survival of the party a key element of his campaign for the top job.
Mr Corbyn's close ally, the shadow chancellor John McDonnell, said Mr Smith must stop "blackmailing" party members with the threat of a split.
Mr McDonnell told Sky News it was "not right" for Labour members voting in the contest to be given an ultimatum and called for a return to an "amicable" and "comradely" contest - before branding Mr Smith the "disunity candidate".
It comes as Mr Smith and Mr Corbyn prepare to face each other at a debate in Cardiff on Thursday night in front of party members.
Ahead of the contest, Mr Corbyn has unveiled his 10 pledges "programme" to rebuild Britain, including a £500bn (€590bn) investment scheme over seen by a national investment bank over the next decade.
On Wednesday, Mr Smith set out his vision for the leadership, unveiling a "triple lock" of pensions overhaul, benefit changes and a higher minimum wage. Last week he made 25 policy pledges.
As Mr Corbyn and Mr Smith prepare to go head-to-head, the latest court case over the leadership voting process is due to be heard later at the UK's High Court.
A crowd-funded group of party members are challenging the decision of Labour's ruling National Executive Committee to ban £3 (€3.50) supporters from voting if they did not join by 12 January unless they pay a further £25 (€29.50).
Meanwhile, a YouGov poll shows the Conservatives enjoying their biggest lead over Labour since November 2009.
The poll shows the ruling party with 42% support, compared to 28% for Labour. UKIP is on 12% support, with the Liberal Democrats at 8%.