The jury is still out on cricket's controversial Decision Review System (DRS) a month after it made its World Cup debut.

The International Cricket Council (ICC) has said that the technology has improved correct umpiring verdicts by more than seven percent in the World Cup.

But not everybody is convinced about its efficacy and the Board of Control for Cricket in India (BCCI), the world's richest cricket body, remains a steadfast opponent.

- Images: India, England tie on 338 runs

- Video: Dhoni slams Umpire Decision Review System

Infuriated by Ian Bell's apparent letoff for lbw in the tied India-England match, BCCI secretary N. Srinivasan wrote an angry letter to ICC chief executive Haroon Lorgat, saying the incident exposed the inadequacy of the system.

India captain Mahendra Singh Dhoni termed it "adulteration of technology with human thinking".

The ICC was forced to make a statement explaining the implications of the 2.5 metre rule which was used to rule Bell not out.

Ireland captain William Porterfield was left fuming at Sri Lankan umpire Asoka de Silva's decision to give Gary Wilson out lbw despite replays showing that he had offered a shot to a delivery that appeared to hit him outside the line of off-stump.

The ICC was again prompt in reprimanding the Irish captain for publicly venting his ire.

- Images: WI thump plucky Ireland

The technology used by the ICC to improve correct umpiring verdicts in this tournament has been far from satisfactory without the use of the cutting edge Hot Spot technology.

New Zealand questioned the DRS when Nathan McCullum was denied a caught-and-bowled decision against Sri Lanka's Mahela Jayawardene.

Jayawardene was lucky to survive after the third umpire gave the benefit of doubt to the batsman though the catch looked clean from replays.

Tensions flared following the decision as stand-in New Zealand captain Ross Taylor and the bowler had a heated debate with the on-field umpires.

Taylor was asked if cricket should return to the old days when the fielders' words were taken for granted.

- NZ, Lanka in a 'catch' controversy

"I guess it depends on the person. Look at Jacques Kallis, he asked the fielder if they caught it, and he trusts the word of the fielder," Taylor said.

South Africa's Kallis decided to walk after asking England wicketkeeper Matt Prior if his edge had carried.

"I guess you put it up to the batsman to make the decision and at the end of the day, you just hope the technology is right. And if technology's not right, well then don't use it," Taylor said.

Strong words but, given that a decision can change the course of a match in the tournament, Taylor can not be blamed.

The DRS has also had an effect on umpires who are put under the spotlight when a successful review overturns their decisions.

Former Australian test umpire Darrell Hair is also sceptical about the possible overuse of technology.

"I cannot help wondering how much of a confidence dent will be left on some of our ICC umpires when they begin to continually have decisions overturned," he wrote in the journal of the New South Wales Cricket Umpires and Scorers Association.

Sri Lankan de Silva, one of the elite panel umpires, has already paid the price after a poor tournament and did not feature in any role in the ICC list for the quarter-finals.

Both the system and the umpires are bound to come under further scrutiny when business end of the tournament kicks off on Wednesday.