The model reportedly demanded euros for a Pantene advert

Gisele Buendchen is said to be keen to avoid the US currency because of uncertainty over its strength.

The Brazilian, thought to have earned about $30m in the year to June, prefers to be paid in euros, her sister and manager told the Bloomberg news agency.

However, Ms Buendchen, 27, declined to comment on her pay arrangements.

"Contracts starting now are more attractive in euros, because we don't know what will happen to the dollar," Bloomberg quoted Patricia Buendchen, the supermodel's sister who also acts as her agent, as saying.

However, the AFP news agency later reported that Patricia Buendchen had denied the story.

"It's a joke by some journalist, it's ridiculous," she was quoted as saying.

"We never talk about Gisele's contracts, and even less so the money involved," she added.

More attractive

Last week, the dollar hit long-term lows against the euro, the British pound and the Canadian dollar.

According to Brazil's weekly magazine Veja, when Ms Buendchen signed a deal to represent Pantene hair products, she demanded that the brand owner, Procter & Gamble (P&G), paid her in euros.

P&G was reported as saying that it could not comment on details of the contract.

There are also reports that she will be paid in euros for a deal with Dolce & Gabbana to promote its The One fragrance.

But the supermodel's agent in New York, Anne Nelson, denied that there were any special currency arrangements.

"When she works in Europe she gets paid in euros, when she works in the US she gets paid in dollars, when she works in Brazil she gets paid in reais and so on," she said.

She also pointed out that Ms Buendchen lived in New York and so needed US dollars.

'Still negative'

Last month, billionaire investor Warren Buffett said that he was not confident about the strength of the dollar.

"We are still negative on the dollar relative to most other currencies, so we bought stocks in companies that earn their money in other currencies," he said of his Berkshire Hathaway investment vehicle.

And Jim Rogers, a former investor partner of George Soros, told the BBC that if he was buying currency now, it would be the Chinese renminbi, the Japanese yen and the Swiss franc, not the US dollar.

The dollar has slipped amid US interest rate cuts, which have been trimmed to 4.5% after standing at 5.25% in September.

This means that investors are looking to buy other currencies that will give a higher rate of return.