An off-duty ambulance worker in the US is being honoured for saving the life of pastor at a wedding.

Valeria Franco was catering at the wedding in Paterson City, New Jersey when Rev Anthony Palmer collapsed whilst in the middle of delivering the vows.

"I said it would require patience, love, kindness, and then I passed out," Rev Palmer told NBC4 New York.

The church leader had gone into cardiac arrest.

It was then when the 22-year-old sprang into action performing chest compressions on Rev Palmer without any equipment for 30 minutes until paramedics arrived.

Paterson City Hall honoured Franco at event on Tuesday, thanking for her for “heroic efforts”.

"This is the last thing you would ever expect at such a joyous occasion," Paterson Mayor Andre Sayegh said.

"But by the grace of God, Franco, who was a caterer at the wedding, happened to be there and resuscitate the pastor. She is literally a lifesaver. Because of this, the City of Paterson recognises her heroism."

Rev Palmer, who also attended the event at Paterson City Hall, thanked Franco for saving his life.

"I just want to thank you [Franco] because the greatest responsibility we have is to serve people," Rev Palmer said.

"You weren't really working that day, and I am so glad that you are willing to put aside and accept your responsibilities. I would not be here today and my wife would not be here today if it wasn't for your service. I thank you and I pray for your success."