The man was detained at his home in Cardiff this morning on suspicion of offences under the Computer Misuse Act and the Regulation of Investigatory Powers Act, which covers issues of surveillance.
According to media reports, the man is not connected directly to the activities of journalists, or any specific news organisation.
A Scotland Yard spokesman confirmed that he is currently being questioned at a police station in the Cardiff area.
The man is the sixth person to be arrested as part of Operation Tuleta, the police investigation into alleged computer hacking.
It is running alongside the Operation Weeting probe into phone hacking and the Operation Elevden investigation into allegations of corrupt payments allegedly made by journalists to police and high profile individuals.
To date, 24 people have been arrested under Operation Weeting and 41 under Operation Elveden, including two journalists from the Sunday Mirror and Daily Star Sunday earlier in the week.
> Man arrested in police phone hacking probe
> Phone hacking: Prosecutor could decide on cases this month