Chancellor of Germany Angela Merkel arrives at the first session of the Valletta Summit on migration | Getty Angela Merkel’s cabinet revolt The chancellor and her top aides split over her refugee policy.

BERLIN — Some of the strongest opposition to Angela Merkel’s refugee policy has started to emerge from an unexpected quarter: her own cabinet.

In recent days, two longtime Merkel allies — Finance Minister Wolfgang Schäuble and Interior Minister Thomas de Maizière — publicly questioned the government’s strategy and called for tougher policies to slow the refugee influx.

Schäuble, speaking in Berlin late Wednesday, warned that Germany faced a potentially destructive “avalanche” of refugees.

“Avalanches can be triggered when a somewhat careless skier heads down the hill, shifting just a little bit of snow,” Schäuble said, drawing what many viewed as a not-so-subtle analogy to Merkel’s September decision to welcome thousands of refugees stranded in Hungary.

The criticism has laid bare a growing division between Merkel and conservatives in her party who are demanding a tougher line. Though Merkel’s hold on the chancellorship remains firm, the open challenges to her authority from senior cabinet officials reflect the increasing difficulty she faces in keeping not just the German people, but her own party behind her in refugee crisis.

Germany registered 758,000 refugees through October and will cross the million threshold by the end of the year if the current rate of new arrivals holds. Local communities across the country complain that they don’t have the resources to cope. Recent polls suggest that the public’s confidence in the government’s strategy is diminishing.

Support on the slide

Merkel’s conservative alliance has felt the brunt of that frustration at the polls. In September, the conservatives seemed invincible, with 42 percent of respondents in the country’s benchmark political poll saying they would vote for the alliance. That support has since dropped to 37 percent.

The right-wing Alternative für Deutschland, which advocates stricter border controls and limits on refugees, has seen its support double to 8 percent.

Schäuble’s move to distance himself from Merkel is particularly significant. A former interior minister and his party’s longest serving member of parliament, Schäuble counts as the conservatives’ éminence Grise.

He remained loyal to Merkel throughout the Greek crisis, even when the two disagreed on policy. Associates say Schäuble’s dissent on the refugee question is not political calculation but rather reflects his conviction that Merkel’s open-door policy was a mistake.

Hints of the policy disagreements within Merkel’s cabinet emerged last month when she appointed her chief of staff, Peter Altmaier, to coordinate the government’s response to the crisis. The move was viewed by many in Berlin as an attempt to sideline de Maizière, whose ministry is responsible for handling asylum seekers.

“I believe de Maizière’s plan is necessary. We don’t have unlimited capacity” — Wolfgang Schäuble

De Maizière, the chancellor’s former chief of staff and longtime confidante, hasn’t yielded. Late last week he announced that his ministry would guarantee Syrians asylum for only one year and only allow refugees to bring their families to Germany after two years of residence.

Currently Syrians are granted asylum for three years and can request that their families be allowed to join them.

The issue of including refugees’ families is a sensitive one. Allowing family members to come means that Germany could have to take in millions more people. But refusing them will spur whole families to flee, putting the lives of many women and children at risk, refugee groups warn.

The plan, which the minister announced on German radio Friday, created an uproar, in part because he hadn’t consulted Merkel.

For Merkel, the timing couldn’t have been worse. The day before, she had managed to assuage the Bavarian wing of her party by agreeing to a package of measures aimed at making it easier to deport rejected asylum seekers. To secure the compromise, she also had to convince the center-left Social Democrats, who govern in coalition with her conservatives. The Social Democrats were also caught off guard by de Maizière’s plan and accused Merkel’s allies of trying to trick them.

Within hours, de Maizière was forced to backtrack.

Then, on Sunday, a widely watched German political talkshow featured a prominent guest: Wolfgang Schäuble.

“I believe de Maizière’s plan is necessary,” he said. “We don’t have unlimited capacity.”

Merkel and Altmaier didn’t know Schäuble was going to throw his weight behind de Maizière. After hearing from a reporter of the Schäuble appearance via Twitter, Altmaier responded, “What did he say?”

Schäuble’s message got through. On Monday, the CDU’s executive board endorsed de Maizière’s proposal to limit families, a clear sign that the party wants Merkel to take a tougher line.

A day later, the interior ministry announced it had also reinstated the Dublin rules for Syrians. Once again, Merkel and her chief of staff were left out of the loop.

Those regulations require refugees to apply for asylum in the first EU country they enter. The ministry relaxed the rules in August, an administrative recognition that the Dublin system had ceased to function.

The decision to reinstate the rules, which came in late October but was only announced this week, is largely symbolic. German courts have ruled that Berlin can’t send refugees back to Greece, the point of entry for most, because conditions there for refugees aren’t considered humane.

Nonetheless, the move sends a clear message that Germany’s Willkommenskultur, or culture of welcome, is fading.

A problem shared...

Merkel has responded to the pressure by trying to convince the rest of Europe and Turkey to take more of the burden. So far, she has little to show for those efforts. While EU countries agreed last month to allocate 160,000 refugees across the region over the next two years, only a handful have actually been placed.

The issue was again the focus at a meeting of European leaders in Malta on Thursday. Germany plans to raise the matter again at this weekend’s G20 summit in Turkey. The EU plans a separate summit with Turkey on the refugee issue before the end of the year.

The problem for Merkel is that unlike during the euro crisis, resolving the migration crisis depends on factors, including the war in Syria, over which she has little influence. Meanwhile, the refugees keep on coming.

Merkel sought to calm her unsettled MP’s at a meeting of the conservative parliamentary group on Tuesday. She and de Maizière insisted they were acting in unison, participants said.

Despite the challenges, Merkel still enjoys the support of most of MPs. But for her to keep it, she will have to show progress on limiting the flow of new arrivals.

“Everyone agrees that the system isn’t working and something needs to be done,” one MP said. “The problem is that nobody knows what the solution is.”