SYDNEY (Reuters) -Anglo American has frozen hiring globally after its pledge this week to simplify the miner that is the target of a $43 billion bid by Australia's BHP, according to an internal memo issued by Anglo and reviewed by Reuters.

Anglo laid out plans on Tuesday to refocus its company on energy transition metal copper while spinning out or selling its less profitable coal, nickel, diamond and platinum businesses, as it moves to fend off the world's biggest miner.

The London-listed miner has rejected BHP twice, saying its proposals continue to significantly undervalue the company.

"Following yesterday's announcement of our plans to unlock significant value through a simplification of our portfolio ... it is appropriate that we put in place a freeze on the recruitment of all non site-based permanent employees and contractors across all Businesses and Group Functions," People and Organisation Director Monique Carter said in the memo.

"In instances where formal written offers have been made to a candidate, we will honour those commitments however no new offers should be made," Carter said, adding the freeze also applied to consultants beyond those already contracted.

Anglo did not immediately respond to an emailed request for comment.

Australia's mining and energy union said on Wednesday it would seek urgent meetings with Anglo to discuss workers' job security.

Anglo shares closed up 0.2% at 26.48 pounds on Wednesday, below BHP's latest offer of about 27.53 pounds per share.

BHP's options to take over Anglo are narrowing as it approaches a May 22 deadline to lodge a binding offer.