Government Chief Whip Andrew Mitchell will have a "difficult time" in his new role, Tory MP David Davis has warned.
Mr Davis, who ran against David Cameron for the leadership of the Conservative Party in 2005, also branded those seeking a current leadership challenge "daft".
He told Parliament's House magazine: "Writing letters is daft. We are in the middle of a national crisis in economic terms. It is not a time for introspection."
Mr Mitchell, who previously ran Mr Davis's campaign in the contest for the Tory leadership, was reported to have pulled out of the Conservative Party conference this weekend following claims that he called Downing Street police officers "plebs".
Mr Davis said: "He will have a difficult time. What does a Chief Whip have at his fingertips to deploy normally? Well, a mixture of charm, rewards, appeals to loyalty - all of those are diluted at the moment.
"There are very few jobs to be given out. They are going to have to steer the Parliamentary party through a time when it is not at all clear that our allies are still going to be our allies. It's going to be very, very difficult.
"Andrew is a clever lad, a capable character who's been a whip before. He's experienced, he's been through hard times in government before. If he asks for my advice, I'll give it."
Mr Davis also urged the Prime Minister to "have a plan" on Europe.
He said: "The Europe Minister, the Foreign Secretary and the Prime Minister have got to have a plan. At the moment I don't have a feeling that the party or the Government knows explicitly where it's going.
"The explicit answer to the European issue, whether it's eurozone or the more general European membership issue, is a big renegotiation and multiple referendums."
Mr Davis also touched upon the risks posed by Ukip to the Conservatives.
He said: "Ukip's appeal is not just about Europe. They basically present themselves as an alternative Conservative party. Whether it's law and order or whether it's green policy. It's like a Conservative primer. We want to watch it."
In the same edition of the publication, newly appointed Justice Secretary Chris Grayling spoke of the need for the party to give "some symbolic statements" to voters on Europe following Mr Cameron's EU veto.
Mr Grayling said: "Now when I talk about EU veto moments, I don't mean necessarily more vetoes, but I think we will need some symbolic statements between now and the next election that say to the people who voted Conservative at the last election and indeed some of those who voted with their feet and stayed at home - or some of those who voted for Ukip - something that says to them 'actually we like the idea of a second term majority Conservative Government, we believe and have confidence that it would do the kind of things we want it to do' and it's quite important we send messages to that effect."