President Barack Obama will on Tuesday move to reform US export rules, hoping to boost trade while hampering the sale of sensitive technology.

Capping a year-long review of weapons controls, Obama will tell a Washington non-proliferation conference that previous rules were fractured, making it difficult for some legitimate firms to do business.

"These reforms will focus our resources on the threats that matter most," Obama said in recorded video remarks. "They'll help us not just increase exports and create jobs, but strengthen our national security as well."

The reforms will include more specific definitions of goods that need export licenses and restructuring how requests are dealt with.

The move is expected to result in around 32 percent of items on the munitions list being "decontrolled."

The new rules will build "higher walls around the export of our most sensitive items while allowing the export of less critical ones under less restrictive conditions," Obama said.

Struggling against a dogged economic downturn, Obama has vowed to double US exports in the next five years.

But the latest part of that drive has spurred some concerns that rules will be watered down to help trade.

"I'm concerned," said Jeff Abramson, deputy director of the Arms Control Association.

"There are a number of good things that have been needed for a while... but I'm afraid this approach could mean more things going to people without us having a sense of where they have gone."

He also expressed fears that the reforms could hurt efforts to hammer out new global norms for the arms trade.

"To weaken our system now hurts the prospects for a good treaty, which is in our national interest," he said.