DECATUR, IL (DOW JONES)--U.S. regulators are speeding their assessment of new high-tech crop seeds following "frustrating" delays to the oversight process, the head of DuPont Co's (DD) agribusiness unit said.

DuPont's Pioneer Hi-Bred International business has been playing catch-up with rival Monsanto Co. (MON) in introducing genetically modified seeds and traits that boost crop yields by providing more resistance to bugs and herbicides.

Paul Schickler, Pioneer's president, said a "bit of uncertainty" had emerged among regulators assessing the new products and pushed the approval process from an average of 18 months to around three years.

Schickler said Pioneer had ploughed more resources into regulatory affairs as part of efforts to introduce six new biotech traits between now and 2013.

"We are getting signals that they've had the message and are speeding up," Schickler said in an interview at the Farm Progress trade show in Illinois.

Canadian regulators this week approved new Pioneer seed traits for corn and soybeans. Their U.S. counterparts have already cleared the soybean trait, and Schickler expects approval for the corn to follow soon.

Cindy Ragin, a spokeswoman for the USDA's Animal and Plant Health Inspection Service, said reviews of biotech seeds are each unique and can be longer or shorter depending on individual circumstances.

"There's no set time frame for review of these things. Some take longer than others. There could be different reasons," Ragin said. "Anything could happen during that process where we may have to go back and ask for more information [from the company]. We may have to conduct additional studies. It's not formulaic."

Proponents of the high-tech seeds maintain they are essential to boost yields to meet expanding global food demand given constraints on useable land and water shortages. Critics, notably in European countries that continue to ban genetically modified crops, said long-term effects on the ecosystem have yet to be full tested.

Robb Fraley, Monsanto's chief technology officer, acknowledged in an interview that the costs associated with securing regulatory approval had increased.

However, better testing procedures had kept the overall cost of bringing the new seeds to market constant. A new trait costs between $100 million and $150 million and can take up to 10 years from formulation to launch, he said.

Fraley said the sharp spike and subsequent decline in agricultural commodity prices hadn't affected its targeted spending on research and development, which remains at about 10% of revenue. Monsanto evaluates its pipeline of projects at least twice a year and uses a three-year weighted average of crop prices in its analysis.

Schickler said the slowdown in regulatory approval wasn't restricted to the U.S., though he acknowledged there remained "growing pains" in the oversight of an industry that is just 12 years old.

The investment required to develop new GM crops has seen the sector concentrated around six multinationals, and Schickler said he was unsurprised by the recent announcement that U.S. competition officials are examining parts of the sector - including marketing of GM seeds - for possible abuses.

"There's a lot of investigative [work] to get a sense of whether there is an issue or not," he said.

DuPont and Monsanto are embroiled in an often-heated spat over alleged patent infringement. Monsanto has also bristled at accusations from a lobby group with ties to DuPont about its dominance of the GM seed market.

-Doug Cameron, Dow Jones Newswires; 312-750-4135; doug.cameron@dowjones.com

(Bill Tomson contributed to this story)