New Zealand's World Twenty20 squad have been hit by some serious bouts of gastro, with the fast bowler Tim Southee and the batsman Rob Nicol too ill to travel with the team from Colombo to Kandy ahead of their opening match against Bangladesh, New Zealand Cricket has confirmed.

Southee felt unwell on Monday morning, and was unable to take part in New Zealand's warm-up loss to South Africa. Nicol was ill overnight and it was decided that neither he nor Southee should accompany the team on the journey to Kandy.

Instead, both have remained in Colombo under the observation of the New Zealand team doctor. Southee has been taken to hospital to be treated for signs of dehydration.

"Southee reported to medical staff that he felt unwell yesterday morning," New Zealand cricket said in a statement. "He was not able to attend the warm-up match against South Africa and subsequently displayed symptoms associated with gastro-enteritis.

"Nicol was sick over-night and could not travel comfortably this morning so also remain in Kandy under observation of the team doctor. Because Southee showed signs of dehydration it has been decided that he will receive re-hydration treatment at the local hospital.

"If sufficient improvements are made today the pair will travel to Kandy this afternoon."

"We're pretty diligent in how we go about things but we can't contain everything," New Zealand coach Mike Hesson said. "I think they'll be up either tonight or first thing in the morning, it's just precautionary."

The spin bowler Daniel Vettori, meanwhile, has also suffered from stomach trouble but has recovered sufficiently to travel with the rest of the squad. "Dan's still pretty low in terms of energy levels but getting back up," Hesson added.

Their match against Bangladesh will take place on Friday.