Jesse Ryder was confined to the team hotel missing out on the second day of the tour game against New South Wales © Getty Images

New Zealand batsman Jesse Ryder has contracted a mystery illness ahead of the first Test against Australia starting next Thursday in Brisbane. Ryder has been quarantined from his team-mates and placed on an intravenous drip.

With Brendon McCullum also struggling with a back problem, New Zealand have called up two reserves with Peter Fulton and Gareth Hopkins flying out to join the squad.

Lindsay Crocker, the New Zealand manager, said Ryder was vomiting before and after batting in the first innings of the tour game against New South Wales at the SCG on Thursday. He was attended by the doctor on duty at the ground soon afterwards, who recommended the illness should be treated as viral.

"He woke up yesterday feeling unwell and being ill," Crocker told NZPA. "We quarantined him, basically, took him back to the hotel. He's not eating so we rehydrated him. He spent the night quietly and he's woken up this morning not feeling a good deal better which is a little concerning because we hoped it had run through by now."

Ryder was confined to the team hotel on Friday morning and did not take the field for New South Wales' innings, with the allrounder Grant Elliott acting as a substitute. But Crocker said Ryder's illness did not yet place him in doubt for the first Test, although there would be major worries if the symptoms continued through the weekend.

"It's run for a day-and-a-half now and he was vomiting again this morning. That's the concern. That time away from eating means he's starting to lose a bit of condition. It's not alarming yet but we want to get him right quickly."

Other New Zealand players had also reported upset stomachs on Friday, though not enough to sideline them. "There's a bit of diarrhoea amongst the group but no one's reported in sick beyond that," Crocker said. "We're keeping careful watch in case it's something that spreads."

Ryder made his Test debut in New Zealand's most recent Test series in Bangladesh. He scored 169 runs in the two matches at 56.33, including 91 in the first innings of the second Test in Dhaka.

New South Wales also had similar concerns on the first day of the tour match when the spinner Beau Casson was sidelined by food poisoning. New Zealand play two Tests in Australia before they host West Indies for two Tests, two Twenty internationals and five ODIs.