The editors of The Sun and The Times and the former chair of the Press Complaints Commission are to give evidence to the inquiry into press standards.
Sun editor Dominic Mohan and editor of The Times James Harding have both been recalled to give further evidence to Lord Justice Leveson's inquiry.
It is understood Mr Harding will be asked about alleged email hacking at his paper.
Scotland Yard detectives are investigating claims that a Times journalist, named as Patrick Foster, accessed the emails of Lancashire detective Richard Horton in 2009 to unmask him as the author of the anonymous NightJack blog.
Mr Harding told the inquiry in January that one of his reporters was issued with a formal written warning for professional misconduct for gaining unauthorised access to an email account.
The editor provided Lord Justice Leveson with further evidence about the incident in a letter made public on January 25.
The inquiry has heard that The Times fought a High Court battle to name Mr Horton as the writer of the NightJack blog after the reporter told his managers he had tried to access an email account.
Mr Mohan, who told the inquiry last month that his paper could be a "powerful force for good", has also been recalled. He is expected to be questioned on The Sun's Page 3, which features pictures of topless models.
His appearance comes as a new poll commissioned by women's charity Platform 51 reveals that more than two-fifths of women in the UK would support a ban on the use of topless images in daily newspapers. The charity said 2,013 UK adults aged 18 and over were polled online from February 3-6 this year.
The results showed 42% of women would support a ban. The research also found 41% of younger people, aged 18-24, would support a ban, compared to 28% of those aged 45-54.