Black Caps call for back-up

Peter Fulton has not played a Test since Bangladesh at Wellington earlier this year

New Zealand have sent for reinforcements amid concerns over the availability of wicketkeeper Brendon McCullum and top-order batsman Jesse Ryder for next Thursday's first Test against Australia in Brisbane.

Peter Fulton will link up with the squad for the duration of the tour on Monday in the event Ryder, who spent most of yesterday on a drip, fails to overcome the effects of the virus in time, while Gareth Hopkins will also arrive on Monday as an emergency squad member.

McCullum failed to return to the field after tea on day two of the Black Caps' tour match against NSW at the SCG after complaining of back spasms.

But while the tourists wasted no time issuing the SOS call across the Tasman, the vice-captain could still take his place when play resumes tomorrow.

"He is hoping to be on the field tomorrow morning but we won't know that until we see how he scrubs up in the morning," team manager Lindsay Crocker said.

"Again with him there's a range of possibilities in regards to next week, firstly and hopefully he'll be fine to participate fully in the match, batting and keeping.

"The other possibility of course remains that if his back isn't right he may only participate as a batsman.

“The third possibility is that if his back really does cause him problems over the next few days it's of course possible that he doesn't play at all."

Brendon McCullum's absence would represent a huge loss on a hard tour for the Kiwis

Quizzed on the nature of McCullum’s injury, Crocker revealed: "He's had a bit of a stiff back for the last two or three days and today during the course of the second session he was feeling a bit of spasms in the back.

"He has had a history of having a sore back, it's kind of an occupational hazard with Brendon... it's certainly not something that's new to him."

Meanwhile, Kiwis seamer Iain O'Brien conceded the five catches his side put down today severely hampered their cause as the Blues built a 43-run lead at stumps.

"They hurt us and we could of rock-and-rolled them for 250 had we taken the five catches," O'Brien lamented.

"We dropped guys that went on to get good scores."

Blues opener Phillip Hughes, who struck a commanding 64 before flailing at a wide delivery, made no secret of his side's desire to ram home their advantage over the remaining two days.

"You don't play an international side every day of the week and to get the opportunity is great," the 19-year-old said.

"It's always (about building) momentum so hopefully we can win this game and definitely it will give us momentum going into a Sheffield Shield game against Queensland next Friday."

Having dismissed the Black Caps for 266, NSW closed day two on 309 for six to establish a lead of 43 with four wickets remaining thanks to half-centuries from Hughes, Moises Henriques (55) and Dominic Thornely (85).