Australia batsman Quiney's stint in England has been ended by a shoulder injury and Essex have responded by signing the 24-year-old Black Caps opener, who is expected to be a key figure for his country in the two-Test series which begins on Thursday at Lord's.
He will be available for the county in all formats, around his international commitments, and is set to make his debut in June 2's Yorkshire Bank 40 clash with Scotland.
Coach Paul Grayson said: "We are delighted to be signing Hamish. He is an attacking opening batsman who will definitely benefit us in both the Yorkshire Bank 40 competition and Friends Life t20 too.
"I was very impressed with how he played for New Zealand this winter against England and Hamish comes highly recommended from some good judges in the game, so he will be a great acquisition for us I'm sure."
Rutherford, the son of former Kiwi captain Ken, made 126 against England Lions in a recent warm-up for the Test series and marked his Test debut earlier this year by scoring 171 against England.