The mother of Stephen Royds, the New Zealander who kept his girlfriend's body on dry ice for nearly a year in the United States, says she is looking forward to her son coming home.

Stephen Royds, who was jailed for four years in a minimum security US prison after pleading guilty to two drug charges in October last year, is likely to be freed from prison and deported next April.

Royds, 46, was arrested at the Fairmont Hotel in Newport Beach near Los Angeles in March last year, after police found him with 54 grams of cocaine bundled in dozens of small packets.

A search of his room turned up the body of his girlfriend, Monique Felicia Trepp, 33, stuffed in a plastic tub and preserved with dry ice.

Tests later showed she died from a drug overdose.

Royds' mother, Sally Royds, told The Southland Times she had not seen her son since 1995 and was looking forward to welcoming him back to Queenstown.

Mrs Royds said her son wrote most weeks and described her son's health as "not great".