ANAS Sarwar has refused to make any comment following the suspension of Scottish Labour MP Brian Leishman from the party.
The Grangemouth MP was kicked out of Labour on Wednesday alongside three of his colleagues.
Leishman is said to have been kicked out of the parliamentary Labour Party over voting against the Government and criticism of its policies in the media.
Also out are English MPs Neil Duncan-Jordan, Chris Hinchliff and Rachel Maskell, the latter of which led a recent welfare rebellion which threatened to challenge the Government's majority.
Two Labour MSPs have come out in support of Leishman, with Alex Rowley saying he was "one of the hardest working MPs in the country".
Mercedes Villalba also said suspending Leishman was the "wrong decision" adding: "Brian Leishman is exactly what a Labour MP should be: A committed socialist and trade unionist prepared to fight for his constituents without fear or favour.
"The whip should be returned.”
The National approached Scottish Labour on Thursday morning to ask whether Sarwar would clarify who he was supporting: Keir Starmer or Leishman.
But by a stated deadline on Thursday afternoon reporters had still received no response.
Sarwar consistently said he was behind welfare reforms put forward by Labour and the SNP said he "must be feeling totally humiliated" after Starmer was forced to perform a screeching U-turn on the bulk of the plans.
By gutting the bill, ministers were able to see off a significant rebellion by voting down the wrecking amendment by 328 votes to 149.
Starmer is reportedly attempting to restore party discipline before the summer recess beginning on Tuesday.
Leishman has been a consistent critic of Starmer’s Government during the Prime Minister’s first year in Number 10. In a recent interview with the BBC, he said he was not proud of the party’s first year in office.
Leishman said following his suspension: “I wish to remain a Labour MP and deliver the positive change many voters are craving.
“I have voted against the Government on issues because I want to effectively represent and be the voice for communities across Alloa and Grangemouth.
“I firmly believe that it is not my duty as an MP to make people poorer, especially those that have suffered because of austerity and its dire consequences.”
