Police investigating the murder of a newly-married doctor and the shooting of her husband in Antigua are doing "everything" to find those responsible.

Catherine Mullany, formerly Bowen, was shot in the head in a suspected robbery at a luxury hotel on the Caribbean island.

Her physiotherapist husband Benjamin remains in a critical condition in a hospital intensive care unit after being shot in the neck.

The Commissioner of Police for Antigua and Barbuda said the inquiry into the murder was still continuing.

"We are all deeply shocked and saddened -- this is the first visitor homicide in over ten years and it is a situation we never want to see repeated," Gary Nelson said.

"Everything is being done to bring the perpetrators of this crime to justice."

The couple, both 31, were on the last day of their honeymoon when robbers apparently burst into their cottage as they slept.

They had been on the island for two weeks after marrying at a church in the Swansea valley in South Wales on July 12.

Andy Liburd, news editor for the Antigua Sun, told reporters: "As far as I know there are six people in custody, but I don't think they will have been placed under arrest yet.

"Here in Antigua, people can be in custody for two days before police either arrest or release them."

The couple's parents are due to arrive in Antigua today.

Click here to read more on this story from Sky News.