Protests have begun over a reform of the patent laws being considered by the US government.

Dean Kamen, inventor of the Segway and holder of 440 patents, was one of a group of inventors who have testified to the US Senate against the proposed law.

The legislation seeks to limit the damages for patent infringement, and allow patents to be challenged more easily after they have been issued.

The bill is being supported by Microsoft and Cisco, which claim that they are at the mercy of companies that own a patent on small portions of much larger applications and use this to reap substantial pay outs.

But Kamen warned that the legislation, if passed, would be disproportionately harmful to inventors.

"You do not shut down the national pastime of baseball because some players are using steroids," Kamen told the San José Mercury News.

"You can go after 'trolls' and other bad actors without unintended consequences that are harmful."

The bill has already passed the US House of Representatives and is being considered by the Senate.

The legislation has now provoked a number of small companies to band together as the Innovation Alliance to oppose its progress.

"We know that 40 per cent of patents are held by small business," said Innovation Alliance spokeswoman Susan Mora.

"We can only guess at the number of patents currently in the coffers of the largest corporations that started with discoveries made by individual inventors, small businesses and America's publicly funded universities.

"These are the drivers of innovation. To put this new cost on innovators so that patent infringers can reduce their supposedly soaring litigation costs is unconscionable."