Southern Cross Healthcare clients are having to wait hours on hold to contact the company and up to six weeks to have claims paid.
The country's largest health insurer, with about 800,000 clients, has been behind on claims for some time but denies it is in financial strife.
Reports suggesting the companyis struggling to pay out claims because of a lacklustre performance in its invested cash reserves have been denied by chief executive Roger Bowie.
Today, Mr Bowie told NZPA the claims processing holdups were due to installation of a new computer system, which had "a small glitch".
