Zienia Merton was a British actress born in Burma. Her mother was Burmese, and her father half-English, half-French. She was raised in Singapore, Borneo, Portugal, and England. Her childhood wish was to become a dancer, and upon securing her father's agreement she was registered at the dancing and acting school led by the "Arts Education Trust" in Tring, Hertfordshire, UK. But, as Zienia progressed, she found herself rather more interested in modern dance. Enjoying public performance, and taking into consideration her changing interests, she found herself gravitating towards the acting field. Without any official training, she began her career as an actress in the 1960s while still a teenager.
Merton's first significant science-fiction credit was as Ping-Cho in the 1964 Doctor Who story Marco Polo, long since lost in its original form. Her other early television appearances included Strange Report (1968), The Six Wives of Henry VIII (1970) and Jason King (1971). She was a lead actress as Christina in the 1971 Dennis Potter TV adaptation of Casanova with Frank Finlay, and appeared on The Benny Hill Show in 1972, playing the wife of Hill's Chow Mein character. Her film roles included Catch Us If You Can (1965), a brief appearance as an oriental high priestess in the Beatles' film Help! (1965), as Ting Ling in the film The Chairman (1969) with Gregory Peck, and The Adventurers (1970).
Following Space: 1999, Merton appeared in many popular television series including Grange Hill, Return of the Saint (1979), Bergerac (1983), Angels (1983), Tenko (1984), Dempsey & Makepeace (1985), Lovejoy (1986), Crime Traveller (1997), Doctors (2001), Dinotopia (2002), Casualty (1986 – 2002), EastEnders (1998 – 2003), The Bill (1999 – 2005), Judge John Deed (2006), Coronation Street (2008) and Wire in the Blood (2008). Merton re-joined fellow Space: 1999 star Ian McShane for the 1986 Lovejoy episode "The Axeman Cometh".
In December 2008, Zienia Merton filmed a guest role for the eighth episode ("Samaritan") of the ITV drama Law & Order: UK. Although the series premiered on 23 February 2009, some episodes were held over for broadcast as "Series Two". "Samaritan" was first transmitted on ITV1 on 11 January 2010.
In May 2009, Merton returned to the world of Doctor Who, 45 years after her appearance in Marco Polo, to record a special episode of The Sarah Jane Adventures (starring Elisabeth Sladen). In the two-part episode "The Wedding of Sarah Jane Smith", broadcast on BBC One on 29 and 30 October 2009, she worked alongside special guest star David Tennant.