Indian authorities were investigating Tuesday a former state chief minister accused of siphoning off hundreds of millions of dollars to buy himself mines in Africa and properties across Asia.

Tax officials allege Madhu Koda, now a federal member of parliament, plundered more than 400 million dollars while he was mines minister and later chief minister of the impoverished eastern state of Jharkhand.

Officials allege Koda, along with two senior colleagues, bought coal mines in Liberia and properties and other assets in locations ranging from Indonesia and India to Hong Kong and Thailand.

- We have identified the main (alleged) players -- there are many players who are still not identified - Ujjwal Chaudhary, a senior income tax official, told AFP after authorities conducted dozens of raids.

India has long been notorious for political graft and the raids came just ahead of a week-long national drive against official corruption by the country's Central Vigilance Commission, a national anti-corruption watchdog.

- The entire scam was worth at least 20 billion rupees (423 million dollars) - a senior government source told AFP.

Koda, aged 38, has denied the accusations, calling them a conspiracy hatched by political opponents.

Under questioning since the weekend, he was hospitalised in intensive care on Tuesday in the Jharkhand state capital Ranchi after complaining of chest problems, officials said.

Two of the politician's closest aides, whose rags-to-riches tales -- one was a milk vendor and another a cement supplier -- mirror Koda's own rise from poverty, are also under investigation.

The money was generated by kickbacks from the granting of iron ore mining leases and contracts for rural electrification in Jharkhand, income tax officials said.

- This will hit the beneficiaries as well -- all those who managed to get the leases - the source said. - The net is getting wider by the minute. -

Last year India, the world's second-fastest growing economy, slipped further in campaign group Transparency International's corruption index from 72nd to 85th in a list of 180 countries.

Questions about Koda's business dealings have dogged him since he took over as mines minister in 2003, and last month authorities ordered an investigation.

A large chunk of the illegal funds were allegedly channelled abroad through Mumbai to a middleman in Dubai.

Koda, who pursued a lavish lifestyle with frequent foreign trips, served as chief minister of the state from 2006 to 2008 -- at the same time as retaining the mining ministry.

He is now an independent MP in India's lower house of parliament.

- The cash was going out and would come back through a maze of companies - the government source said, alleging the money was channelled through his two closest associates.

Much of the money reinvested in India went into malls, property and corporate stakes in companies, officials alleged.

Born to a poor farming family, Koda worked as a miner and did other menial jobs before joining politics. He quit as chief minister in 2008 when faced with the prospect of losing a confidence vote.

He is being questioned on suspicion of money laundering, corruption and other allegations and has been told to appear before tax authorities on November 6.