Investigators have seized electronic devices from two homes in relation to the leak of CCTV footage of Matt Hancock in a clinch with his aide.
The Information Commissioner's Office said officials raided two addresses in the south of England on Thursday and confiscated computers and electronic equipment.
Mr Hancock was forced to resign as Health Secretary last month after images emerged of him kissing his aide Gina Coladangelo.
The images, obtained by the Sun, appeared to be taken from CCTV footage from Mr Hancock's Whitehall office.
The information watchdog confirmed today it was investigating after EMCOR Group - the firm running CCTV at the Department of Health and Social Care - submitted a report of an alleged data breach.
The ICO said in a statement: "As part of the investigation, ICO teams searched two residential properties in the south of England on Thursday July 15 2021.
"Personal computer equipment and electronic devices were seized as part of the operation and the ICO's enquiries into alleged breaches of section 170 of the Data Protection Act 2018 continue."
The leak of the footage sparked concern across Whitehall over potential security implications.
Steve Eckersley, ICO director of investigations, said: "It's vital that all people, including employees and visitors to public buildings, have trust and confidence in the protection of their personal data captured by CCTV.
"In these circumstances, the ICO aims to react swiftly and effectively to investigate where there is a risk that other people may have unlawfully obtained personal data.
"We have an ongoing investigation into criminal matters and will not be commenting further until it is concluded."
Mr Hancock tried to cling onto his post as Health Secretary after the explosive images emerged of him kissing his old university friend Ms Coladangelo.
He apologised for breaching his own social distancing rules, as the footage was said to have been filmed in early May - before restrictions on social contact was relaxed.
Boris Johnson initially stood by him, with his spokesman saying the PM considered the matter closed after Mr Hancock's apology.
But Mr Hancock resigned the following day amid widespread public outrage and a deafening silence from Tory MPs.
He was replaced by former Chancellor Sajid Javid as Health Secretary later that day.
Ms Coladangelo also resigned from her post as a non-executive director for the Department of Health and Social Care.
