Countries hit by conflicts in the Middle East have lost $12 trillion over two decades through squandered development and livelihoods, said a new study by India-based Strategic Foresight Group launched on Friday.

The work was immediately endorsed by several countries that have acted as major peace brokers in the region, including Norway and Switzerland.

The report, by the India-based Strategic Foresight Group, revealed a massive price tag for all sides since 1991 due to the destruction wrought by the Israeli-Palestinian conflict, strife in Lebanon and the US invasion of Iraq.

But it also underlined the equally huge potential of a comprehensive peace for countries and territories in the region and their inhabitants, predicting that it would unleash growth from the Mediterranean deep into the Gulf.

Sundeep Waslekar, who headed the study with experts from the regions concerned, said individual incomes for Israelis and Palestinians were half what they would be if peace had been accomplished at the Madrid conference in 1991.

For Iraqis, per capita incomes had been cut to one third over the same period, he added.

In the event of peace, an average Israeli family would increase its income by $4,429 per year in 2010 even if Israel paid compensation to Palestinian refugees and moved more than 150,000 settlers out of the West Bank, according to the report.

The income of Palestinian territories would more than double even if they remained in their current shape and the study suggested roughly equal gains to be had on both sides of the fence.

Unveiling the report at the United Nations offices here, Waslekar said the choice was fundamentally down to one between continued "devastation" and a peace accord.