Ala replaces Muammer Guler, one of three cabinet members who resigned after their sons were detained in a graft probe that erupted on December 17. Guler, who like Erdogan had called the case baseless and a plot, sacked or reassigned dozens of police officers involved including the chief of the force in Istanbul.
"He (Erdogan) is trying to put together a cabinet that will not show any opposition to him. In this context, Efkan Ala has a key role," Kemal Kilicdaroglu, the head of the biggest opposition party CHP, said in remarks carried by Turkish media.
"Erdogan has a deep state, (his) AK Party has a deep state and Efkan Ala is one of the elements of that deep state," added Kilicdaroglu, using a term that for Turks denotes a shadowy power structure unhindered by democratic checks and balances.
During his three terms in office, the Islamist-rooted Erdogan has transformed Turkey, cutting back its once-dominant secularist military and overseeing rapid economic expansion. He weathered unprecedented anti-government protests that swept major cities in mid-2013.
But the corruption scandal has drawn an EU call for the independence of Turkey's judiciary to be safeguarded and has rattled stocks and the lira, with the currency falling to a historical low of 2.1025 against the dollar on Monday.