Shares in the flagship firm of troubled Indian conglomerate Adani rose almost 15 percent Tuesday, clawing back some of its recent huge losses after saying it would repay more than $1 billion in loans.

Investors wiped out around $120 billion in value from the group owned by tycoon Gautam Adani after claims of accounting fraud by short-seller US investment group Hindenburg Research on January 24.

The collapse raised concerns about the group's ability to raise fresh financing to pay down its debts. It cancelled a share sale, and reportedly also a bond issue, last week.

But India's biggest conglomerate said Monday it was repaying early loans worth $1.1 billion, in a move meant to reassure investors.

The Adani Ports subsidiary said Tuesday it would also repay debts of around 50 billion rupees ($605 million) and slash by half its capital expenditure in the next financial year.

Adani Enterprises, the group's flagship firm, soared as much as 25 percent on Tuesday, with trading suspended three times on the way up.

The shares closed up 14.6 percent -- although they are still down by more than half since the start of the year.

Other group companies were mixed, with Adani Transmission rising five percent but closing 0.77 percent lower, and Adani Total Gas down five percent and trade suspended again.

"The markets are happy that they prepaid a chunk of their borrowings. This is a refreshing sign of confidence," markets commentator Srinath Sridharan told AFP.

Fitch Ratings said Tuesday that Indian banks' exposure to the Adani group was "insufficient in itself to present substantial risk to the banks' standalone credit profile".

- 'Largest con' -

Hindenburg accused Adani of a "brazen stock manipulation and accounting fraud scheme" in "the largest con in corporate history".

Adani artificially boosted the share prices of its units by funnelling money into the stocks through offshore tax havens, Hindenburg said.

The conglomerate has rejected the claims as a "maliciously mischievous" reputational attack.

Last week tycoon Adani, 60, insisted the "fundamentals of our company are very strong, our balance sheet is healthy and assets robust".

His personal wealth has more than halved, seeing him fall from number three in the Forbes real-time list of the richest people in the world to 17th as of Tuesday.

India's political opposition says Adani's closeness with Prime Minister Narendra Modi, with both men from Gujarat state, has allowed him to win contracts unfairly and avoid proper oversight.

Parliament has been adjourned several times in recent days with opposition parties calling for a probe into Modi and Adani's links.

Rahul Gandhi from the Congress party, which staged protests Monday, told parliament on Tuesday that the two men already had close ties when Modi was Gujarat's chief minister.

"The result of that was tremendous growth and expansion of his businesses in Gujarat," Gandhi said.

"Then the real magic began in 2014 when Modi comes to Delhi (as prime minister) and Adani –- who was number 609 on the global rich list -– reached number two within a few years."