"I believe one of the main problems with the West Indies at the moment is the gap between regional cricket and international cricket," King told a news conference.
"They are trying their best but if you go and watch regional cricket closely the lines that they bowl aren't conducive to taking wickets at international level.
"We've talked with all the coaches and to a man they've have been supportive of the approach that we are trying to put forward.
"That means all our bowlers, including spinners, bowling attacking rather than defensive lines. We need to put pressure on opposing sides."
Eight of the 12 bowlers used by the West Indies have taken the 34 wickets the home side have claimed so far..
South Africa have used just eight bowlers and six of them have taken the visitors' 45 wickets.
South Africa clinched the series when they won the third Test by an innings and 86 runs in Bridgetown on Sunday to take an unassailable 2-0 lead in the four-match rubber.
The fourth Test starts in St John's on Friday and if South Africa win they will be the fourth country to reach 100 Test victories after Australia, the West Indies and England. They are currently on 99 wins from 302 Tests.
West Indies captain Shivnarine Chanderpaul said his team were determined to salvage something from the series.
"We are going into the match in a positive frame of mind and we're looking for a win," Chanderpaul told a news conference.
"We've been trying hard, we've had meetings where everybody has contributed.
"That makes my job easier, and I'm happy with that. But I'm not happy with our results."
Chanderpaul said the West Indies needed to improve all aspects of their game.
"To win we have to play better cricket than South Africa, and that's all round - batting, bowling, fielding," he said.
West Indies: Shivnarine Chanderpaul (captain), Courtney Browne, Chris Gayle, Wavell Hinds, Ramnaresh Sarwan, Brian Lara, Narsingh Deonarine, Dwayne Bravo, Daren Powell, Fidel Edwards, Tino Best, Dwight Washington.
South Africa: Graeme Smith (captain) Nicky Boje, Mark Boucher, AB de Villiers, Boeta Dippenaar, Herschelle Gibbs, Andrew Hall, Jacques Kallis, Charl Langeveldt, Andre Nel, Makhaya Ntini, Shaun Pollock, Ashwell Prince, Jacques Rudolph, Monde Zondeki.