Rupert Murdoch is expected to fly into the UK on Thursday to take charge of the crisis at The Sun after 10 journalists were arrested over alleged corrupt payments.
There is anger at the tabloid that News Corporation's Management Standards Committee (MSC) - formed to clean up the company following the phone hacking scandal - gave police the information that led to the arrests.
Mr Murdoch has already said he will not sell or close The Sun, and will seek to reassure staff further during his visit to the offices of his British papers in Wapping, east London.
Five Sun journalists - including the deputy editor, picture editor and chief reporter - were held by Scotland Yard detectives on Saturday on suspicion of making improper payments to police and public officials.
Four current and former employees of the paper were arrested a fortnight earlier, and a senior reporter was detained in November. They have all been bailed and none has been charged.
Trevor Kavanagh, associate editor of The Sun, which is Britain's top-selling paper, has strongly criticised the Metropolitan Police's handling of the arrests and voiced concerns about the MSC's actions.
"There is unease about the way some of the best journalists in Fleet Street have ended up being arrested on evidence which the MSC has handed to the police," he said on Monday.
News International refused to confirm precisely when Mr Murdoch will arrive in London, but said it would be before the end of the week.
Meanwhile, a source has said the investigation into alleged corrupt payments by Sun journalists involves "suspected criminality over a sustained period of time" involving tens of thousands of pounds, Reuters reported today.