The government is allowing British arms manufacturers to sell to some of the most dangerous and repressive regimes in the world, two charities claim. A dramatic rise in the sale of arms components to these regimes undermines the government's own ethical policies, say Oxfam and Amnesty International.

The Foreign Office says the conclusions of the charities' report are unfounded. Foreign office minister Baroness Symons said the parts are always assessed against stringent criteria. The government has banned weapons sales to unstable countries.

But the charities say parts made in the UK are reaching countries like Zimbabwe, Israel, Indonesia, Uganda, Colombia, Nepal and the Philippines, even though the sale of complete weapons systems to these countries is banned.

Once abroad the components, ranging from gun barrels to guidance systems, could easily assembled into completed systems by regimes involved in military conflicts and abuses of human rights, said the report.

"We are concerned that weaker standards of licensing of these items, especially given their increased prominence in the export market, create a dangerous new loophole that will allow UK-provided arms components to contribute to suffering around the world," it stated.

It accused the government of putting the interests of the defence industry ahead of concerns about human rights abuses.

There was particular concern about small arms, with the number of licences issued for the export of assault rifle components alone rising from 10 in 1998 to 41 in 2002, including 23 "open" licences which allow multiple shipments.

Oxfam policy director Justin Forsyth said the government was putting lives at risk by setting up "false and dangerous double standards".

"These aren't simply nuts and bolts we're selling," he said.

"These components include firing mechanisms, bomb making equipment, guidance systems and gun barrels.

"Whether a machine gun comes in pieces or ready made, the suffering it can cause in the wrong hands is just the same."

Baroness Symons said it was simply not the case" that the government was allowing arms to be sold through a loophole.

"We take full account of what the components might be used for...We simply would not issue a licence where there was an unacceptable risk of it being misused or diverted," she said.