South Africa expect Kemp to be a key figure at the World Cup

The United Cricket Board wants Kemp to take a break before a one-day series in Sri Lanka in August and the Champions Trophy in India later in the year.

"I am really sorry to be leaving Kent earlier than expected," said Kemp.

Kent plan to fill the gap by signing Dwayne Bravo after West Indies finish their current series against India.

I just hope it's not the last we see of him for Kent Paul Millman Kent chief executive

But they may have to look for a second new face with Andrew Hall already selected by South Africa for the two-match Test series which precedes the one-dayers in Sri Lanka.

"This situation does highlight how increasingly difficult it is for counties generally to plan their playing resources to deliver to supporters' expectations," Kent's chairman of cricket Graham Johnson commented.

"We reluctantly accept the South African board's overiding wish to ensure that Justin is properly prepared ahead of the forthcoming Sri Lanka tour and the 2007 World Cup and are very sorry to see him go."

Kemp has made two Championship centuries for Kent this summer, including a 56-ball effort against Durham that is the fastest in the tournament so far.

He recently hit seven sixes in an innings of 54 not out off 20 balls to help them beat Sussex in the C&G Trophy at Tunbridge Wells.

Kent chief executive Paul Millman said he hoped Kemp would return in the future.

"We always felt he would deliver for us, and he certainly has done this season," Millman told BBC Radio Kent.

"I think everybody that saw his knock at Tunbridge Wells will always remember it as a stunning piece of hitting."

"I just hope it's not the last we see of him for Kent. We wish him well on the international scene and let's hope our paths cross again."