But the 29-year-old has now recovered and sees the Auckland tournament as ideal preparation for the Australian Open. She reached the semifinals in Melbourne last year and was the beaten finalist two years earlier.
Martinez will be joined in Auckland by fellow Spaniard Angeles Montolio who, with a ranking of 23, is likely to be top seed.
With Anna Kournikova already confirmed, tournament director Richard Palmer is now looking at the possibility of her and Martinez playing doubles together.
"Both have excellent doubles records," he said. "They are managed by the same group so I might just explore that possibility.
"Having Conchita here is a real coup. It now seems unlikely we will have a top-20 player this time, but with players like we have already it promises to be a closely fought tournament.
"I will be surprised if the cut-off this time is not lower than last year. It could come in at around 80."
Defending champion Meilen Tu, at present ranked 45, is a confirmed starter.
Martinez will be one of the highest-profile players to play at Stanley St. Last here as a 17-year-old - in her second professional year - she went on to win the then-WTA tournament in Wellington.
She has 32 singles and 10 doubles titles, and has amassed close to $US10 million in prizemoney - the eighth-best on the all-time list.
Montolio will come to Auckland after an impressive year in which her end-of-season ranking has risen from 60 a year ago to a career-high 23.
She captured her first singles crown at Estoril, Portugal, in April and followed that two weeks later by winning in Bol, Croatia.
Organisers of the men's Heineken Open have also attracted some big names, with Wimbledon champion Goran Ivanisevic the latest to confirm his entry for the January 7-12 tournament.
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