Andy Burnham will vow to grow the UK economy and set out Labour's fiscal rules in a speech next week as he prepares to become the next Prime Minister.
The former Greater Manchester Mayor is widely expected to replace the embattled Sir Keir Starmer, who announced his resignation in emotional scenes outside No.10 on Monday.
Nominations for Starmer's replacement will be open from July 9 to 16, and Burnham could take office as soon as the following day if no other candidate can gather enough support to run.
The Times reports that Burnham will use a speech early next week to seek to boost his economic credentials and soothe market uncertainty about his premiership.
He is expected to promise to reduce national debt, lower the cost of borrowing and produce a "credible" plan for growth within the existing fiscal rules.
The Times reports he will choose between Ed Miliband, the Energy Secretary; Wes Streeting, the former Health Secretary; and Shabana Mahmood, the Home Secretary, when selecting his Chancellor.
Concerns have already been raised by ministers that Miliband would not be a popular choice for the role and could cause a market revolt due to not being pro-business enough.