Coach Mark Robinson has admitted financial as well as cricketing reasons were behind Sussex's decision to sign Dwayne Smith.

He has launched a passionate defence of the West Indian's arrival as a Kolpak after criticism that he would stop the development of younger players.

The 25-year-old, who has played ten Tests and 71 one-day internationals, has signed until the end of 2010 after registering as a Kolpak and effectively turning his back on Caribbean cricket.

He was initially recruited as a stop-gap overseas player to ignite Sussex's Twenty20 Cup campaign. But although he finished as leading wicket-taker and scored 185 runs he never quite fulfilled expectations - a bit like the Sharks' campaign itself.

Barbados-born Smith is unlikely to figure in four-day cricket this season but he will have a key role in Sussex's bid to win the Pro40 League when it starts on July 20.

Yet his true worth might not become apparent until 2010 when a domestic Twenty20 League seems certain to start.

It is likely to mean counties operating flexible playing staffs of local and more overseas players arriving for short-term stays.

And there is every possibility that the Kolpak loophole will be closed by the European Union by then although players such as Smith who are already employed would continue to be protected.

Robinson said: "It's inevitable with the way the game is changing that you are going to see players migrating in and out of English cricket.

"In 2010 cricket will be different. I'm sure there is going to be a domestic Twenty20 league and you to have a squad who can adapt to that. Dwayne Smith is a cricketer who puts bums on seats and as coach I have a duty to build a squad which is going to help fill this ground and thus support the Championship team."

Smith becomes the third Koplak signing at Hove alongside fellow Bajan Corey Collymore and Murray Goodwin.

The ECB are also proposing to toughen their stance on Kolpaks by halving the annual handout of £800,000 they give to each county but increasing the amount paid for England players they produce.

Some counties, notably Northamptonshire and Leicestershire, have been criticised for filling their squads with Kolpaks, a scenario Robinson insists will not be repeated at Sussex.

"We won't end up like Northants and full of Kolpaks," he insisted. "In our last Twenty20 game against Kent a week ago we had two non-English qualified players in the side. At times more might play but at the moment I can't envisage Dwayne and Collymore playing in the same one-day side for instance.

"But one-day cricket is changing, money has come into the game and you need a strategic plan for limited overs and Championship cricket. However, I also know I have a duty to produce English-qualified players."

Robinson is confident Sussex can get the best out of Smith who has struggled to live up to expectations after scoring a hundred on Test debut against South Africa in 2003.

"Dwayne Smith is going to be an outstanding one-day cricketer and how much he improves in four-day cricket remains to be seen," added Robinson. "But we wouldn't sign him if we didn't think he is capable of improving.

"He is possibly an under-rated bowler and an over-rated batsman, as daft as that sounds. He holds the seam up, bowls in good areas at 80mph-plus and he is deceptive because he comes off such a short run-up.

"We would have liked a few more runs from him in Twenty20 but he is capable of winning us games and has fitted in really well around the squad."

Robinson does not believe that Smith will block the pathway into the first team for youngsters in the squad.

He added: "There are no guarantees but what he won't do is stand in the way of our youngsters, as some people have suggested.

"They all can't play at the same time but this season we have used 20 of the 21 players on the staff. In fact, if anything, too many have played and that is reflected in our results.

"But they have all got experience. Some stand up while others get exposed but they learn. Ollie Rayner, Chris Liddle, Ragheb Aga and Rory Hamilton-Brown have all played in the Championship this season and our history shows that if they are good enough youngsters play here.

"If they don't kick on it won't be because they havent had opportunities."