Nearly 1,000 US veterans attended an event where free cannabis seeds were handed out Getty

US war veterans have been given free marijuana seeds to help ease injuries and post traumatic stress syndrome from wars in Vietnam, Afghanistan and Iraq.

Nearly 1,000 vets attended at event in Colorado - where cannabis has been legalised - to find out how the drug can be used as an alternative to prescribed medicines.

Products showcased to former troops at the Operation Grow4Vets event included grow-your-own seeds and cannabis cookies, which can be used instead of daily doses of pills.

"It isn't going to hurt them as much as the prescription drugs," Roger Martin, an army veteran and director of Operation Grow4Vets, told the Springs Colorado Gazette. "I just need something to take the pain away during the day."

Martin said since Colorado became the first US state to legalise the commercial sale of cannabis in 2012, veterans have moved there to take advantage of the lenient laws.

According to statistics, nearly one fifth of soldiers returning from Iraq and Afghanistan suffer from post-traumatic stress syndrome, while almost 30% returned from Vietnam with the disorder.

As well as relieving their physical pains, the drug has been credited with helping veterans sleep better at night.