Petrobras, Brazil's state-run oil company, could be declared in technical default on some of its foreign debt as early as Tuesday if bondholders pursue efforts to force it to speed up its assessment of losses in a giant corruption scandal.

The push, led by New York-based Aurelius Capital, applies to $54 billion of Petrobras bonds governed by U.S. law in New York state. Aurelius, a "distressed debt" fund, is asking investors to put the company into default as "a precautionary step," according to a Dec. 29 letter from the firm reviewed by Reuters.