David Ferrer. Getty Images
Ms Lawson said yesterday's news that world number 10 David Ferrer had pulled out of the tournament with a back injury had not led to requests for ticket refunds.
"Ticket buyers are coming along for the range of international players coming to New Zealand, rather than for one player in particular.
"We are still boasting our best-equal line-up to date which features four world top 20 players."
This year's field includes world number 13 Ernests Gulbis, Roberto Bautista Agut (number 15), Kevin Anderson (16) and Tommy Robredo (17).
The Heineken Open also welcomes the world's best doubles pairing, American identical twins Robert and Michael Bryan.
A wildcard entry has been given to 17-year-old Croatian player, Borna Coric, who organisers say will be "a massive name" in coming years.
Two Kiwis have been given wildcards - New Zealand number one Michael Venus and Rubin Statham.