Marking two decades since the end of a debilitating civil war, Mozambique's president on Thursday said the country must now focus on exploiting its vast resource wealth for the good of everyone.

"Today we still have a very large budget deficit and we still face problems exploiting the resources we have," said President Armando Guebuza during official celebrations to mark the signing of a peace agreement that ended a brutal 16-year civil war.

"We have peace. There is no alternative to peace," he said 20 years after a UN-backed peace accord was penned, signalling the end of a Cold War-fuelled conflict that pitted the Marxist-leaning Frelimo party against Renamo rebels.

The country and government's task now, he said, is "to exploit the wealth we have and ensure that all the people benefit from it".

Mozambique has recently discovered a huge reserve of gas, as much as 100 trillion cubic feet, making it a major energy player and offering hope of prosperity to come.

The war broke out in 1976 just a year after the southern African country had gained independence from Portugal, only to end after a million lives were lost.

It was waged by the Mozambique National Resistance (Renamo), bank-rolled by white minority governments in neighbouring South Africa and what was then Rhodesia, now Zimbabwe.

By the time the war ended, resource-rich Mozambique was ranked among the most impoverished countries on earth.

"So as we celebrate 20 years of the peace accord we should think when possibilities of safe growth arise, this development should be reflected in the whole country and for all Mozambicans," said Guebuza after laying a wreath at the heroes monument.

The official celebrations were held a few blocks from where tens of thousands of people displaced by the conflict, still live in tin shacks. Many of them live on as little as $1 a day.

New gas and coal finds have seen post-war Mozambique turning into a favourite investment destination and one of the fastest growing economies in the world, but the growth is yet to trickle to the majority of the country's 23.4 million people.

The top 10 percent of the population has an income 19 times that of the poorest 10 percent, according to the Africa Progress Panel, an observer group led by former UN secretary general Kofi Annan.