Pace bowler Tim Southee and batsman Rob Nicol remained in Colombo on Tuesday after being struck down with illness just three days ahead of the Black Caps' opening World Twenty20 cricket match in Kandy, Sri Lanka.

Southee didn't play in New Zealand's final warm-up match against South Africa on Monday, but Nicol chipped in with a useful 37 off 36 balls in the nine-run loss in Colombo.

Both have been hit with a stomach bug, which also kept key spinner Daniel Vettori out of the game.

Vettori improved sufficiently to travel with the team but Southee is showing signs of dehydration and is receiving re-hydration treatment at the local hospital. Nicol fell ill overnight and was unable to travel comfortably.

It is hoped the pair will improve enough to travel to Kandy later on Tuesday, where New Zealand's first World Twenty20 is scheduled for Friday against Bangladesh.

The Black Caps had only 11 fit players for their final warm-up match, Kyle Mills and Jacob Oram also sitting out with injuries.

New Zealand bowling coach Damien Wright was called upon to take to the field during South Africa's innings.