On the eve of a conference in London designed to build support for Somalia's official government, Abdulhakim Haji Faqi told The Daily Telegraph that an arms embargo first imposed in 1992 should now be abandoned.
"To live peacefully within ourselves, we need our military to be equipped properly – and that is why we need completely to lift the arms embargo," he said.
In March, the UN eased the embargo, allowing the supply of small arms to the official government, but maintained the ban on heavy weapons.
Mr Faqi said this had made no difference so far in the fight against insurgents.
"Although the [small] arms embargo has been lifted close to two months ago, still we were not able to bring even one extra bullet or one extra AK [rifle] because of lack of funding."
Mr Faqi's task is to weld clan militias into a single national army. Last year, al-Shabaab, the radical Islamist movement that is allied to al-Qaeda, was finally expelled from the capital, Mogadishu, and much of southern Somalia, including Kismayo, a vital port.
But this was largely achieved by 18,000 African Union troops, drawn mainly from Uganda, Kenya and Burundi.
Mr Faqi's goal is to build a new army capable of securing Somalia without foreign personnel.
"We should build our professional national army within three years, but it will really depend on the support we receive from our international partners, including the UK, the US and European Union," he said.
At present, Mr Faqi said the army has fewer than 4,000 trained soldiers. One training centre in Mogadishu is producing another 1,000 every four months. The goal is to open two more training camps and deploy 28,000 troops by 2016.
But Mr Faqi said this depended on funding from Britain, America and the EU. "Al-Shabaab has been defeated, but they are still dangerous," he said.
"They lost fighters, they lost territory, they lost their finances, but still they are a danger.
"In this fight, we need to be together with international partners, such as the UK and US."
Mr Faqi added: "Margaret Thatcher said 'this is no time to go wobbly'. We have to stick together – we have to fight against al-Shabaab."