A senior Conservative backbencher has said he hoped chief whip Andrew Mitchell will be able to "draw a line" under the row over his clash with police.
But the vice-chairman of the influential 1922 Committee John Whittingdale declined an opportunity to state his personal confidence in Mr Mitchell, and said it was too early to say whether he retained the full confidence of Tory backbenchers.
The Committee will meet on Wednesday to discuss the case, and senior members will then pass on to Prime Minister David Cameron their assessment of backbench opinion over whether Mr Mitchell should keep his job.
The Sutton Coldfield MP has denied calling police officers "plebs" after they refused to let him cycle through the main gates at Downing Street on September 19. However, he has conceded that he swore and did not show enough respect, and has apologised to the police officer involved, who accepted his apology.
Labour will later table a motion calling for him to be docked £1,000 from his salary - roughly the same amount he could have been fined for swearing at an officer.
Mr Whittingdale said he had not yet had time to gauge the mood of Tory MPs since Parliament returned on Monday.
Asked on Sky News whether he felt members of the Committee had "full confidence" in Mr Mitchell as chief whip, Mr Whittingdale said: "I haven't had a chance (to find out). Parliament only resumed yesterday and our first meeting is tomorrow, so no doubt I'll find out then."
When he was asked "Do you personally have confidence in him as chief whip?" he replied: "I think he is an experienced member of the whips' office. He has served there in the past. He is well equipped to do the job.
"This is a very unfortunate incident. I hoped, and I think all of us hoped, that he could draw a line under it. It is distressing that it doesn't yet appear possible to do that, but I hope that it can be done." He added: "I think he has accepted that he shouldn't have spoken as he did, and he has apologised for it. Everybody makes mistakes."
Mr Mitchell was barracked by Labour MPs when he appeared on the Government frontbenches on Monday, and faces a further ordeal at Prime Minister's Questions on Wednesday, when he is expected to be present to see Mr Cameron challenged over the affair.