"We are investing substantially. The company is embarking on a $5 billion programme of investment over the next five years," he said in an interview to 'The Times' daily at Davos.
Mittal was confident about the prospects for the steel industry, even though it appeared to be at the top of its cycle.
"All the world's economies are doing well, except Europe, so I am confident that demand will continue to keep steel commodity prices high."
Denying the accusation that he was an asset stripper, Mittal blamed the media for creating this impression.
However, he admitted that one disastrous deal in Ireland in 1996, when he bought an Irish company for a nominal one pound and later had to close it when he could not make it work, added to the perception.
Mittal spoke about his latest deal, in which the Mittal Steel Group bought a 37 per cent stake in the Chinese manufacturer Hunan Valin Iron and Steel for $314 million.
Mittal Steel will overtake Luxembourg-based Arcelor as the world's largest steelmaker in April when it completes the $4.5 billion purchase of US' International Steel Group.
With his takeover of the US firm, Mittal's company will become the world's largest steel producer with pro forma shipments last year of $57 million, revenues of $31.5 billion and profits of $6.8 billion
Meanwhile, the 'Newsweek' magazine in its latest issue carried a detailed report on Mittal's empire describing him as a "hard bargaining entrepreneur" who is creating the world's most far-flung steel empire with operations in 14 countries. "Times had changed, but steel had not changed," he says.
"Our suppliers and our customers had consolidated their businesses, spent the money for modernization and become global. In steel, there was a total disconnect between [any] two countries."
So, the report says, Mittal started connecting things. But the report says the Mittal model is not without its chinks.
The sheer size of Mittal Steel (which produces about 30 million tons more per year than the nearest rival) means that it is the most exposed to a downturn in this cyclical industry.
Mittal disagrees, "The U.S. market will always have high-end, just-in-time needs that cannot be met by China, India or Brazil."
But perhaps more worrying, Newsweek says, are accusations that Mittal has steered profits from acquisitions to his family company, not his public company, Ispat.
He firmly denies these claims, saying he "always brought deals to the board of Ispat first," which turned them down in some cases because of the risks involved. Last year Mittal received a $2 billion dividend from his family company.
His spending on the lavish house and wedding came at a time when he was cutting costs and laying off workers at various plants, arousing a chorus of criticism, the report says.
Mittal, it says, is curt in response, "These things are part of my private life, and I'm not going to comment on them."