As the public launch of the New Payments Platform gets closer, major banks are feverishly recalibrating their retail and merchant payments services to retain and acquire customers.One segment of the payments market of particular interest to the Big Four is the private health insurance claims market.NAB gained a first mover advantage in the fast-growing niche market in the 1990s when it launched its HICAPS platform.Since then HICAPS has enjoyed a leading position in the health payments segment through alliances with most of Australia's leading health insurers.The service has been a lucrative fee-spinner for NAB, allowing health insurance policyholders to have their claims processed at the time they pay invoices through EFTPOS terminals at doctors' practices.Patients who use the system only pay the difference between the cost of their treatment and the insurer's rebate.While NAB dominates this payments space, other banks are angling for a slice of the HICAPS pie.For a number of years ANZ has tried to elbow its way into the market through its ANZ Healthpoint platform.Anecdotal evidence indicates it has had some success building payments relationships with ancillary health professionals but HICAPS has managed to hold the lion's share of the market.The advent of real time settlement of payments through the NPP should make it easier for other banks to compete against HICAPS.It is understood that ANZ will soon begin marketing a new payments service to health professionals that will be rebranded as ANZ HealthPay.NAB is also investing in new business cases to protect its market position.Earlier this year the NAB Ventures arm bought into a local payments start-up known as Medipass, which offers synchronous online payments and claims processing via a mobile app.