By Louis Charbonneau

UNITED NATIONS (Reuters) - U.N. arms embargoes inevitably fail because international arms trade is a virtual free-for-all due to the lack of regulation for the $70 billion global weapons commerce, the rights group Amnesty International said on Tuesday.

"The United Nations Security Council arms embargoes are always flouted and circumvented and violated because the system of state regulation around the world is not strict enough," Brian Wood, Amnesty's head of arms control and human rights said on the sidelines of a U.N. arms treaty drafting conference.

"There are no common rules. Why? Because there is no arms trade treaty," Wood told reporters.

Negotiators from about 150 countries are gathering in New York through March 28 for a final push to hammer out a binding international treaty to end unregulated conventional arms sales.

Arms control campaigners and human rights advocates say one person every minute dies worldwide as a result of armed violence, and that a treaty is needed to halt the uncontrolled flow of weapons and ammunition that they argue helps fuel wars, atrocities and rights abuses.

Wood said that many U.N. arms embargoes - against Angola, Sierra Leone, Liberia, Democratic Republic of the Congo, the perpetrators of genocide in Rwanda, Darfur, Somalia, Taliban, in the Balkans - turned out to be failures.

"If you look at them in detail ... you will find that they were systematically violated," he said.

Wood said the global arms markets are run by companies, dealers and brokers who use shell companies and off-shore bank accounts to keep themselves immune to national regulation, while many states have few or no regulations in place.

"Over and over again we find the same story," Wood said. "Some states repeatedly make irresponsible decisions to supply (arms). The other element is the networks of traffickers that find it so easy to circumvent the embargoes. And the arms trade treaty needs to address that."

Wood also cited the conflicts in Syria and Mali as further examples of why an arms treaty is desperately needed.

U.S. SAYS WANTS STRONG TREATY

The U.N. General Assembly voted in December to relaunch negotiations this week on what could become the first global treaty to regulate trade for all conventional weapons - from tanks and attack helicopters to handguns and assault rifles - after a drafting conference in July 2012 collapsed because the United States, then Russia and China, wanted more time.

The point of the treaty is to set standards for all cross-border transfers of any type of conventional weapon - light and heavy. It also would set binding requirements for nations to review all cross-border arms contracts to ensure the munitions will not be used in human rights abuses, do not violate embargoes and are not illegally diverted.

British Foreign Office Minister Alistair Burt, in New York for the arms treaty negotiations, told reporters on Monday that London would prefer to have consensus on a treaty but did not want unanimity if that meant accepting a weak pact.

He said the British delegation was not interested in "simply getting everyone to sign a piece of paper that does not take us further forward."

If the conference fails to agree a treaty because it cannot reach the required consensus, diplomats say they can put it to a vote in the U.N. General Assembly to rescue it. If a treaty is approved, national parliaments will need to ratify it.

Some delegations have expressed concern that the United States, the world's No. 1 arms exporter, will try to gut the draft treaty to make it more palatable to U.S. gun supporters.

The United States says it wants a strong treaty. But Obama is under pressure from the powerful National Rifle Association, the leading U.S. pro-gun group, to block the pact. The group has vowed to torpedo the convention's Senate ratification if Washington backs it at the United Nations.

U.S. Secretary of State John Kerry voiced conditional support for the treaty on Friday, saying Washington was "steadfast in its commitment to achieve a strong and effective Arms Trade Treaty that helps address the adverse effects of the international arms trade on global peace and stability."

But he did not promise U.S. support. He repeated that the United States would not accept a treaty that imposed new limits on U.S. citizens' right to bear arms, a sensitive political issue in the United States.

Washington opposes the inclusion of imports and exports of ammunition in the treaty, a view Burt said Britain does not share. Human rights groups say the treaty would be meaningless if it did not include ammunition.

(Reporting by Louis Charbonneau; Editing by Jackie Frank)