British chancellor says other EU countries privately voiced doubt about the commission appointment in the face of need for reform

European leaders privately share David Cameron's concerns about appointing Jean-Claude Juncker as the next president of the European commission, George Osborne has said.

After Iain Duncan Smith warned that a failure to embrace reform would result in very bleak prospects for Britain's continued membership of the EU, the chancellor described the contrast between the private and public views of EU leaders as a "rather odd phenomenon".

Shortly before Cameron made a last-ditch attempt – in talks in Downing Street with the European Council president, Herman Van Rompuy – to block Juncker, Osborne indicated that EU leaders had expressed doubts about the former prime minister of Luxembourg.

The chancellor told the Today programme on BBC Radio 4: "There is a rather odd phenomenon at the moment which does happen, believe it or not, in politics. People are saying quite a lot of things privately which they are not saying publicly. Privately, a lot of European governments understand that the institutions of Europe need reform, that they are under huge pressures from their domestic populations to deliver stronger economies, more investment into Europe, that Europe needs to better connect as a union with the people on this continent.

"That is quite widely understood amongst European governments. Whether that plays out over the next few days we will see."

Osborne's remarks were echoed by Duncan Smith, who indicated on Sunday that Angela Merkel, the German chancellor, and Matteo Renzi, the Italian prime minister, had privately shared their misgivings about Juncker.

The work and pensions secretary told BBC Radio 5 Live's Pienaar's Politics: "I was talking to the prime minister the other day and he said there are a load of countries there who share his view on this, they think this is the wrong man, the Italians were saying it, many were saying it, even privately, I understand, many Germans say it. But this is the problem with the EU. It's locked in this ridiculous process that because they took a decision before the elections they must somehow stand by that."

The prime minister will tell Van Rompuy that he wants a vote to be held at an EU summit this week if the council president believes that Juncker has sufficient support. The Liberal Democrat leader, Nick Clegg, will also meet Van Rompuy to show that there is cross-party concern about the planned appointment, which moved a step closer at the weekend as the EU's main centre-left leaders threw their weight behind Juncker.

Cameron's tactics are designed to flush out Merkel and Renzi. It is understood that they share Cameron's view that Juncker, a classic Brussels fixer during his 19 years as prime minister of Luxembourg, symbolises the EU's troubled past, which contributed to a high vote for fringe parties on the left and right in the recent European elections.

Merkel and Renzi are also understood to have concerns about the spitzenkandidaten "leading candidates" system, in which the main pan-EU groups in the European parliament nominated a candidate for commission president. Juncker is the candidate of the EPP, the main centre-right group, which won the most seats in last month's election.

Cameron has said the spitzenkandidaten system threatens the power of the EU's 28 heads of government in the European council, who were given the power in the Lisbon treaty to nominate the commission president, taking account of the European elections.

The prime minister will tell Van Rompuy that the leaders supporting Juncker should make clear at the EU summit why they support him and why they support the spitzenkandidaten system. Merkel is backing Juncker after she faced a domestic backlash when she suggested in the immediate aftermath of the elections that she would support a wider range of candidates. Renzi is supporting Juncker in the hope of easing austerity measures.

Van Rompuy wants EU leaders to have a general discussion at a dinner in Ypres on Thursday about the challenges facing the EU over the next five years. He wants to avoid a row in the sensitive setting of the dinner, being held to mark the centenary of the outbreak of the first world war, by delaying discussions about Juncker until Friday afternoon in Brussels. But Cameron has told Van Rompuy that it would be absurd to discuss the challenges of the future without discussing the next commission president.

Osborne said: "The prime minister is arguing from a position of principle about getting the right people and making sure the right people choose the leader of the European commission. Whether it is arguing about economic reform in Britain or economic reform in Europe we start from strong first principles. As you can see in Britain that has worked for us and will continue to work for us."

In a sign of how Juncker's appointment could strengthen the hand of Eurosceptic members of the cabinet, Duncan Smith said the strong support among other EU leaders for him amounted to "flicking two fingers" at the electorate.

"If they give Jean-Claude Juncker a job this is like literally flicking two fingers at the rest of Europe and saying to all the people out there: 'We know that you voted the way you did but you are wrong and we are just going to show you how wrong you are by carrying on as though nothing happened.'"

Duncan Smith warned of grave consequences if the appointment of Juncker were followed by a failure to embrace "drastic change and reform" in the EU. "If they don't do that then it does make the prospect for Britain being in Europe very bleak indeed."