A couple in their 70s are suffering nightmares over a violent armed robbery in which a gunman counted down from 10 as he threatened to shoot them dead.

Police have offered a $350,000 reward for information leading to a conviction over the robbery, which occurred outside a licensed venue in Melbourne’s west last year.

Otwina and Bryan were leaving a staff Christmas party at the Talmage Street venue in Sunshine on December 19 when the incident occurred.

CCTV footage released by police shows a man wearing a balaclava emerging from behind a waste bin holding a shotgun.

Police said the gunman then demanded the building be opened as he pointed the gun at the couple, before assaulting and seriously injuring Bryan and stealing his mobile phone.

Otwina, 78, said the man then started hitting her 79-year-old husband with the gun barrel.

“First he tackled Bryan. He hit him twice, then stabbed him with the barrel. He went down. He then said open the door. I didn’t have the keys,” Otwina said.

“He said ‘if you’re not going to tell me, I’ll kill her’, and he put the shotgun on me. And he started counting down from 10.”

Two other women who had left the venue with Otwina and Bryan were uninjured.

Otwina said she still suffers nightmares as a result of the robbery.

Broken bones, nightmares

The gun failed to discharge twice during the attack, police said.

“It was pretty unbelievable. It was pretty scary,” Otwina said.

Police said if the gun had fired, the injuries would have been deadly.

Bryan’s speech has deteriorated as a result of serious head injuries he suffered during the attack.

“I have to live with it. Bones broken everywhere. I’m deaf in this ear now. My tooth went,” he said.

“I’m nervous of people. Deep down I’m still looking at people’s feet. Because I know this bloke’s feet – the way he shuffled his feet. It lives in your mind.”

Police said the offender had a walkie-talkie in his pants, and was likely communicating with someone else before the robbery.

Detective Acting Senior Sergeant Andrew Eyries described the robbery as “vicious”.

“We have a number of leads, however we don’t have any suspects at this time,” he said.

Police said they believed someone had intimate knowledge of the attack and hoped the reward would encourage someone to come forward.

-ABC