U.S. hedge funds group Elliott International has raised its stake in Danish company Danisco to above 10%, creating fresh uncertainty about DuPont's agreed takeover of Danisco.

Danisco, the food ingredients and enzymes producer, said in a statement to the Copenhagen stock exchange that Elliott International had informed it that it held 10.02% of Danisco's shares as of May 6.

That makes Elliott the biggest shareholder in Danisco. Hitherto Danish pension insurance group ATP had been the biggest shareholder with a 5.1% stake, and Elliott only last month flagged a 5% stake when it crossed that threshold.

Elliott has been accumulating Danisco stock while at the same time rejecting U.S. chemicals group DuPont's January cash bid for Danisco of 665 crowns ($129.6) per share, which DuPont raised a week ago to 700 crowns, for a total of $6.64 billion.

Opposition by Elliott and some other investors to DuPont's friendly acquisition led DuPont last week to raise its bid and extend the offer period to May 13.

DuPont also lowered the acceptance level that it requires of Danisco shareholders to 80% from 90% after owners of 48% of Danisco's stock supported the initial offer.

Some analysts have doubts that the 5% increase in DuPont's offer will be enough, but others said earlier this week that things were going DuPont's way as a number of Danish institutional investors accepted the bid.