Corbyn is widely predicted to lose in a non-binding vote of Labour MPs this afternoon, with results expected to be announced around 5:00pm.
The vote itself will not trigger a leadership election, which requires 51 letters from MPs and MEPs to be sent to party general secretary Iain McNicol.
At the same time resignations have continued to pour in from across the party's front bench, with shadow energy and climate change minister Alan Whitehead quitting this morning.
It is with great sadness that I have resigned as Shadow Energy and Climate Change Minister as of 11am today pic.twitter.com/97JksufgUz— Alan Whitehead (@alanwhiteheadmp) June 28, 2016
Whitehead's resignation is the fourth of the day so far, following shadow justice minister Andy Slaughter and shadow health ministers Barbara Keeley and Andrew Gwynne.
It means 46 ministers and parliamentary aides have now resigned, while shadow foreign secretary Hilary Benn was sacked early on Sunday morning.
30 ministers and parliamentary aides resigned yesterday alone, including the shadow business secretary Angela Eagle, shadow work and pensions secretary Owen Smith and shadow energy secretary Lisa Nandy, while a dozen shadow cabinet members either quit or were dismissed on Sunday.
Almost all have cited Labour's effectiveness in opposition, with many also bemoaning Corbyn's personal ability to lead the party.
However, the Labour leader has remained firm, appointing first a new shadow cabinet, and then attempting to fill more junior roles.
Those wanting to change the Labour Party leadership will have to take part in a democratic election pic.twitter.com/bIAYB0cpwZ— Jeremy Corbyn (@jeremycorbyn) June 27, 2016
Corbyn's reshuffle means that Labour shadow City minister Richard Burgon was last night named shadow justice secretary, although his replacement, and that of Angela Eagle, have yet to be named.