"It is an attempt to further cement his position and use the membership as a means of driving a wedge between the MPs and his leadership", Smith told Murnaghan on Sky News.
His comments came as his ally Clive Lewis, the shadow defence secretary, backed deselection as a "democratic choice" and a Channel 4 Dispatches documentary to air on Monday secretly filmed members of pro-Corbyn pressure group Momentum pushing for mandatory reselections, even though it is not the organisation's official policy.
But Corbyn says he will unite the party after the contest and although he has said there will be changes because of proposals to alter the boundaries - he has denied there will be deselection.
Giving Labour's membership a role in shaping Labour's top team in Parliament would represent a radical and significant shift in policy, particularly since Ed Miliband scrapped shadow cabinet elections by MPs in 2011. "And I'll invite them to work with us".
Mr Corbyn said he would "reach out" to MPs to build an effective challenge to the Government and highlighted Labour successes during his year as leader, including the Tories' U-turns on tax credit cuts and forced academisation of schools. "It's right we'll be discussing elections to the shadow cabinet at the national executive committee this week, as well as who might take part in those elections, and how to ensure proper representation of the regions, nations, general and ethnicity".
These "tutorials" from former senior ministers and shadow ministers would aim to stop them being accused of being incompetent, and improve relations within the parliamentary Labour party and make them more effective in the House of Commons.
The intention is to surround Mr Corbyn with moderate MPs and weaken his ability to impose hard-left policies on the party that MPs believe will never win a general election.
Unfortunately, in terms of the combined number of seats, the Labour Party is likely have much less to gain from a coalition with the Greens than the other parties.
And it's all very well winning the leadership election - and it looks like Jeremy may well - and being relaxed and having more party members.
"If Labour party members re-elect me that will be my second mandate in a year, from a hugely increased membership". An MP who was named on the list told the New Statesman: "With one breath Jeremy calls for unity and for the party to come together and with the next they publish this anonymous hit-list".
Asked whether it was a veiled threat, the leader told Peston On Sunday: "It's not a veiled threat, it's not a direct threat either, it's not any kind of threat".
James Schneider, of Momentum, dismissed allegations the group were pressing for mandatory re-selections.