The Commons culture, media and sport select committee will quiz former News of the World editor Colin Myler and legal manager Tom Crone, along with former legal director Jon Chapman and human resources director Daniel Cloke.
Crone and Myler have disputed claims by News International chairman James Murdoch that he was not aware of a crucial email suggesting hacking was widespread at the defunct Sunday tabloid.
The discrepancy in their evidence particularly pertains to a key message sent in April 2008, known as the "for Neville" email due to its connection to the News of the World's former chief reporter Neville Thurlbeck.
When the email was sent, the paper's royal editor Clive Goodman had already been jailed for hacking into the phones of members of the royal household.
The News of the World insisted that the practice was down to just one "rogue reporter", but the "for Neville" email is thought to have implied that Thurlbeck was also implicated in malpractices.
In July, Murdoch said during a select committee hearing that when he signed off a payment of almost £700,000 to phone hacking victim Gordon Taylor, he did so without knowing all the facts.
However, Myler and Crone later released a statement saying they did inform him of the email, and their evidence today is widely expected to result in James Murdoch being recalled to answer more questions from the MPs.
Chapman and Cloke will appear before the committee at 10.30am today, and Myler and Crone will give evidence to the MPs from 11.30am.
Yesterday, Rupert Murdoch's News International, publisher of The Sun and The Times, confirmed plans to sell its Wapping base in East London - its UK headquarters for 25 years.