Embattled former Sri Lankan president Mahinda Rajapaksa's country home in the southern province has been raided by police who were looking for a luxury sports car but the search drew a blank.

"They raided our house in Tangalle yesterday looking for a Lamborghini car," said Namal Rajapaksa, the former president's elder son and a parliamentarian.

Police spokesman Ajith Rohana said the search was done on a court warrant but it drew a blank.

"They have been harassing us by searching not only our own houses but those of our friends. We can't visit homes of our associates because they get their places searched," Namal said.

He said the police complaint was based on false information that they were hiding a sea plane and tyres of racing cars.

"All they found was a pedal boat used by pre-school children," Namal said.

The search of Rajapaksa's country home comes days after police launched a probe into allegations that his younger brother Gotabhaya ran "death squads" and ordered the murder of a high-profile newspaper editor.

Basil Rajapaksa, the other brother of Rajapaksa and the former economic development minister, has also been accused of being involved in a number of shady deals.

Since Mahinda Rajapaksa's defeat to Maithripala Sirisena in the January 8 election, the state media have been showing visuals of the Rajapaksa family's extravagant life styles.

The visuals of air-conditioned toilets with digital video screens fixed at the official Temple Trees residence have been aired on state television.

During the run up to the polls, the then opposition accused Rajapaksa's sons of owning helicopters, expensive horses from royal stables in the UK and expensive racing cars.

Information on alleged properties of the Rajapaksa family is being regularly given to police since the advent of Sirisena-led new government.

Mahinda Rajapaksa ruled since 2005 and is credited with ending the LTTE separatist war.

His effort to win an unprecedented third term ended in a disaster with Sirisena, a defector from his own party, toppling him with support from joint opposition, ending a ten-year rule.