The Hull North MP and former Minister, last year voted backbencher of the year, faces a battle for her future after the threshold for a selection contest was triggered at a meeting of her constituency Labour Party (CLP) on Saturday.
Peter North, the Hull North CLP chairman, said it would be "improper" to announce the result of the contest before all parties had voted - but Ms Johnson publicly declared the 33 per cent threshold had been met.
In a statement on Twitter, the MP said she is considering challenging the move.
"I am disappointed to have been triggered for an open selection by a small number of members, especially when overall the majority of Hull North Constituency Labour Party members have so far voted to re-select me.
"I am currently considering a procedural challenge to the process."
Labour branches across the country have been putting new rules into practice for the first time in recent months.
The rules, agreed at last year's party conference, state only a third of either local party members or the same percentage of affiliate groups, such as unions, have to vote in favour of a selection contest for it to be triggered.
Those rules are significantly more lenient than previous stipulations whereby half of both local members and affiliates had to support a fresh contest.
Ms Johnson's colleagues have criticised the decision to force the campaigning MP to fight to retain her candidacy against rivals in a seat she has won four times.
And in the current period of political turmoil and with a General Election looming, MPs say they are being distracted from their jobs by the threat of potential deselection.
A meeting of Labour's National Executive Committee is to be held on Monday where officials face calls to suspend the current trigger ballot process.
Barnsley MP Dan Jarvis told The Yorkshire Post: “Diana Johnson is an exceptionally dedicated, experienced and capable MP for Kingston upon Hull North.
"She is devoted to her constituents and is a tireless campaigner for numerous good causes. She is hugely respected by her colleagues in Parliament.
"At a moment of national political crisis I’m sure many will question the wisdom of subjecting hard working decent Labour MPs to a distracting internal selection process.
"At this pivotal moment in our country’s history, our MPs need to be able to fully focus on the extremely important matters currently in front of us.”
As the sitting MP, Ms Johnson will automatically be awarded a place on the ballot paper in the upcoming selection race. But some fear she will face competition from a Momentum-back hard left candidate favoured by party leader Jeremy Corbyn.
First elected under Tony Blair in 2005, Ms Johnson easily fended off a Tory surge at the 2017 snap election, increasing her majority to more than 14,000 - up 1,500 on 2015.
Ms Johnson was promoted to the front bench by Gordon Brown in 2009 to serve as schools minister and she briefly carried out the role of shadow foreign minister under Jeremy Corbyn's leadership before resigning in the wake of the European referendum result.
The former barrister has been one of the central campaigners in the fight for justice for those impacted by the contaminated blood scandal - when the NHS gave blood infected with hepatitis C on close to 4,000 people in the 1970s and 80s.
The centre-left politician won the Backbencher of the Year award in 2018 for her part in securing a public inquiry into the blood scandal.
She is a member of Labour Friends of Israel and was involved in amending the Northern Ireland (Executive Formation) Act in July in a move that legalised abortion in the six counties.
Leeds West MP Rachel Reeves wrote: "You are a brilliant MP Diana and don’t deserve this. We should all be working together to get a Labour Government not trying to deselect hard-working MPs. Solidarity."
Melanie Onn, the Labour MP for nearby Great Grimsby, tweeted: "Whether it's the contaminated blood outrage or baby ashes campaign (amongst other things) Diana Johnson has never stopped fighting for her constituents or those affected in the country.Mr North said: "Kingston-upon-Hull North Constituency Labour Party is currently part-way through a process of consulting the local membership on whether they would prefer to automatically reselect our sitting MP, Diana Johnson, or to move to an open selection in which Diana Johnson would automatically be a candidate.
"Branches of the local party are making a decision on this, within the rules of the Labour Party. We have a number of branches yet to make a decision and it would be improper to announce the results of completed ballots before all branches have had the chance to discuss this matter."
He told The Yorkshire Post that "any decision to hold a selection process would not imply criticism of our MP but rather a desire from our members to have a democratic say over who represents them".
At the meeting of the Parliamentary Labour Party on Tuesday, MPs reportedly requested all incumbents should be automatically reselected to avoid the party being side-tracked by a series of high-profile reselection contests with a national election to face in the coming months.
Prime Minister Boris Johnson will bring another motion forward on Monday, having failed with a similar request on Wednesday, to ask MPs to vote for a snap general election. The bid for a fresh poll is expected to fail, however.
It would need a two-thirds majority in the Commons to pass but opposition parties, including Labour, have ruled out agreeing to an election before the threat of a no-deal Brexit is removed.