Chancellor Angela Merkel's chief of staff said the German foreign minister was in part to blame for the success of the country's far-right Alternative for Germany (AfD) in last week's election.
Peter Altmaier, a longtime confidant to Merkel, told Focus magazine that Foreign Minister Sigmar Gabriel and Martin Schulz, the centre-left's candidate for chancellor, led voters to believe the government "did everything for the refugees and nothing for the Germans."
"This debate was grist for the mill of the AfD," Altmaier said.
Gabriel is a member of the centre-left Social Democrats (SPD), which has been in a coalition with Merkel's centre-right Christian Democratic Union (CDU) for the past four years.
Altmaier noted that the SPD, led by chancellor candidate Schulz, had repeatedly criticized Merkel's handling of the refugee crisis.
On the campaign trail and in a televised election debate, Schulz had attacked Merkel for admitting stranded refugees in September 2015 without adequately involving Germany's European partners.
He also accused Merkel of not being tough enough on EU countries that have not shared in the burden of hosting the migrants.
The AfD, which ran on an anti-immigrant platform, capitalized on the discontent over refugees to emerge as the third-strongest party in parliament after the September 24 election.
Merkel's conservative bloc had their worst result since 1949, casting a shadow over her domestic political prestige, weakening her grip on power and potentially undercutting her standing on the global stage.
The SPD said it will not enter into another coalition with Merkel, who is now trying to form a coalition with with two smaller parties.
