Former Sri Lankan strongman Mahinda Rajapakse Wednesday accused the new government of pursuing a witch-hunt against his family as he and his brother prepared to be interrogated by anti-corruption investigators.

The 69-year-old, who lost a presidential election in January, accused his successor Maithripala Sirisena of trying to intimidate him by portraying his decade in power as riddled with corruption.

Sri Lanka's main anti-corruption panel is to question Rajapakse on Friday over allegations he bribed a high-profile opposition figure to defect and accept a cabinet portfolio just before January's polls.

"They have no evidence. They are making wild allegations. This is a witch-hunt," Rajapakse told AFP in an interview at his home in a suburb of Colombo, where he is protected by police and military guards.

"Neither I nor any member of my family has ill-gotten money. At first, they said I had money in Swaziland, then in Dubai. Show us the money, where is the evidence?

"They said I owned a hotel in Dubai. Then they said all the hotels in Sri Lanka are owned by me and (brothers) Gota (Gotabhaya) and Basil," Rajapakse said. "This is a joke."

Although the former president was initially summoned to appear before the Commission to Investigate Allegations of Bribery or Corruption (CIABOC) on Friday, authorities later agreed he could be questioned at his home following uproar by some of his supporters.

Gotabhaya, who served as defence secretary under his brother and was seen as the real power behind the throne, is due to be grilled by CIABOC investigators on Thursday although he has requested a delay.

The new government has accused Rajapakse and his inner circle of syphoning off billions of dollars during his tenure, in part by inflating the size of Chinese-funded infrastructure projects.

The former and current central bank chiefs are also being investigated over large-scale corruption allegations while several major defence and aircraft deals are being probed over suspicions Rajapakse cronies received kickbacks.

- 'No China bias' -

The new government suspended work in February on a $1.4 billion Chinese-financed project to reclaim land next to the port of Colombo pending a corruption review.

The project symbolised the growth in ties with China under Rajapakse, a trend that upset the traditional regional power India.

New Delhi was particularly irked when two Chinese submarines were allowed to dock in Colombo late last year.

Rajapakse however denied cosying up to China at the expense of India.

"I never favoured China, but only had the interests of Sri Lanka at heart. All the big projects were first offered to India but they didn't take them up," he said.

Sirisena, who served in Rajapakse's cabinet before quitting to stand against his one-time mentor, made the country's heavy reliance on expensive Chinese credit a major plank of his campaign.

Before Sirisena's defection, Rajapakse had been regarded as odds-on for a third term.

But in his interview, he admitted he blundered by calling the elections two years ahead of schedule.

"It was a serious mistake which I regret," he said, adding his astrologer had suggested the election day was "auspicious".

"I have now lost faith in all astrologers," he added with a rueful smile.

Asked if he planned a comeback, Rajapakse said: "I have not retired. I am only taking a rest.

"There is a lot of political instability under the new government... we should have early parliamentary elections to ensure stability."

Sirisena inherited a parliament that supported Rajapakse, but has promised to dissolve the assembly and call early elections.

So far he has failed to push through promised reforms to roll back presidential powers Rajapakse had awarded himself.

Rajapakse, an ethnic Sinhalese, remains popular among big sections of the island's largest community for overseeing the defeat of the Tamil Tiger separatist rebels in 2009.

He was however shunned by many world leaders after refusing to probe claims that tens of thousands of civilians died in the final months of the 37-year conflict.