At a meeting of the ICC's chief executives' committee at the global governing body's Dubai headquarters, officials agreed the number of reviews will be "topped-up" to two after 80 overs of a Test innings.
Currently, teams are only permitted a maximum of two unsuccessful reviews per innings.
The new playing conditions will be trialled from October 1, meaning they will be in force for the Ashes which begin with the first Test in Brisbane starting on November 21.
Wednesday's statement from the ICC came after England's recent 3-0 Ashes series win at home to Australia was beset by numerous rows over the use of DRS, with both sides unhappy at different times.
Things got so bad the ICC took the step of sending their general manager of cricket, Geoff Allardice, over to England to meet the teams midway through the series in a bid to address their concerns.
One repeated complaint centred around the third umpire's use of DRS and the way in which the replay official interpreted their remit while another problem area focused on the reliability of the Hotspot thermal imaging device in detecting thin nicks.
In response to these issues, and a technology trial conducted during the third Ashes Test at Manchester's Old Trafford ground, the ICC said they'd set up a Working Group to look at ways of improving both DRS and the training of umpires.
Officials also suggested a Real-Time Snickometer - currently used by television broadcasters covering matches but not part of the DRS - could be added to the list of tools at the third umpire's disposal.
"The CEC (chief executives' committee) agreed a Working Group be constituted to consider how the ICC should best use technology in umpire decision-making in the future," the ICC statement said.
"The considerations of the group will be wide ranging and include a review of the objectives and philosophies of using technology, the technologies, protocols and procedures as well as the role and training of television umpires.
"It was also agreed that a trial will be conducted whereby a team's referrals will be topped-up to two reviews after 80 overs of an innings.
"This trial will start from 1 October 2013 in all Test matches in which the DRS is used, with the results being monitored and considered by the Working Group."
As for adding 'Snicko' to the DRS, the statement said: "Noting that most of the contentious decisions relate to faint edges, the performance of the Real-Time Snickometer during the ICC Champions Trophy 2013 and the Ashes, and the potential to use this technology to assist the umpires in making these decisions was discussed.
"An independent assessment of this technology will be conducted before a decision is made on its inclusion in the list of approved DRS technologies."
One Ashes controversy that had nothing to do with DRS concerned the umpires' decision to take the players off the field for bad light during the ultimately drawn final Test at The Oval in south London when England were just 21 runs adrift of victory, with the floodlights on.
There has also long been a feeling spectators are also being short-changed by time-wasting tactics such as slow over-rates.
But a meeting of leading match officials has promised a clampdown and the ICC said: "The CEC also endorsed the umpires' intention to become far stricter on poor over-rates and time wasting and to maximise playing time in conditions where it is safe to do so."Meanwhile two white balls, one from each end, will continue to be used during a one-day international innings although this will be reduced to one ball when ODIS are cut to fewer than 25 overs in the first innings.