Police, forensic scientists, dogs and firefighters carried out the searches of two of Cristina Fernandez de Kirchner’s houses in Patagonia and one apartment in Buenos Aires.

The raids come after a judge asked to partially lift Kirchner’s immunity as he investigates bribery allegations during her presidency between 2007 and 2015.

The forces are looking for evidence that the former leader was involved in a scheme in which she and others in her administration accepted millions of dollars from businessmen in exchange for public works contracts.

She denies all wrongdoing.

Kirchner, who is a senator and has immunity from imprisonment, but not prosecution, described the investigation as “shameless”, in a speech on Wednesday.

She said she regretted “nothing”, apart from “not having been intelligent or open enough to convince and persuade people that what we were doing, with its mistakes and successes, improved the lives of millions”.

However, she voted for her immunity to be lifted to allow the search of her three properties to go ahead, and instructed her colleagues to do the same.

So far 15 people have been arrested in the case, including business leaders from construction companies and former officials who served under Kirchner’s administration.

The scandal relates to a batch of records kept by a former driver for a public works official over a 12-year period.

In the notebooks, the driver Oscar Centeno writes about delivering bags of cash from construction bosses to government officials, which has been estimated to be around $160m.