Two United States private equity firms are hovering with a potential buyout proposal for cash-strapped Arrium as the company's desperate board secured an extra week to try and hammer out a deal with its angry banking syndicate, to avert a likely break-up of the business.

Argand Partners and Cerberus Capital Management have continued to crunch the numbers on a full buyout offer after initially making a $1 billion-plus buyout proposal for Arrium's profitable Moly-Cop mining consumables business earlier this year. They haven't yet made a formal offer to the Arrium board on a buyout for the entire company, but have been fine-tuning as Arrium's plight worsened in the past few days.