Burnham was given a round of applause by his senior ministers earlier, as he opened the first meeting of his new cabinet after appointing his top team on Monday.
Appointments below cabinet rank are expected to follow on Tuesday evening, including Scottish Labour leader Anas Sarwar, who is set to be given a seat in the House of Lords so he can join Burnham’s government.
It is thought Sarwar, who rocked Starmer’s premiership when he called for him to resign in February, will become a business minister.
New rules mean he would have to quit his seat in the Scottish Parliament, although a by-election to replace him will not be required as he was elected on the regional list system.
Monday’s wide-ranging reshuffle saw Starmer loyalists such as Rachel Reeves and David Lammy out of government, with Ed Miliband promoted to foreign secretary and Burnham ally Louise Haigh given a big job running the Cabinet Office.
Miatta Fahnbulleh, a Burnham ally promoted into the cabinet as energy secretary, denied he had led a purge of Starmer supporters, telling BBC Newsnight “no one has a right” to be in the cabinet, which contained a “diversity of views”.
Speaking to staff at the Treasury, new chancellor John Healey said discipline over tax and spending would be his “first duty”, as he recommitted to the tax and spending rules set by his predecessor.
But he added that government would seek to make the “fullest possible use of public investment” within the framework, alongside making the most of private and international investment.