At the end of a day-long visit to Lesotho last night, the Taoiseach warned that the kingdom must develop political stability if it is to attract investment and overseas aid.
The first EU head of government ever to visit the politically troubled southern African state, Mr Ahern told the king and political leaders that there was a heavy responsibility on all politicians to engage in constructive politics.
His comments come as the country prepares for elections at the end of this year in an effort to prevent further political unrest.
Mr Ahern, who spent yesterday having political meetings and visiting Ireland Aid projects in Lesotho, travels this morning to South Africa where he will spend four days promoting trade, meeting the President and other political leaders and visiting Irish-funded projects.
Ireland is to spend £6 million on aid this year in Lesotho, where dozens of people were killed in violence which erupted after a disputed election result in 1998.
Following the election, in which the government won 49 of the 50 seats in parliament, £30 million worth of damage was caused when more than 1,000 business premises were destroyed with a loss of more than 5,000 jobs.
Mr Ahern told a banquet in the capital, Maseru, last night that there was a special bond between Ireland and Lesotho "forged through a quarter of a century of fruitful co-operation".
But he added: "In order to attract both investment and development assistance, it is important to have the stability and predictability which well-functioning political processes and a sound public administration can bring."
Earlier the Prime Minister, Mr Pakalithi Mosilisi, assured Mr Ahern that new elections would take place in the state before the end of the year. There had been fears that this election, due under a new electoral system instead of the old "first past the post" model, would be postponed.
Mr Ahern told reporters he had strongly pressed the Prime Minister on the issue of the murder of an Irishman, Mr Ken Hickey, in Lesotho a year ago. Mr Hickey, a retired engineer, ran the Ireland Aid footbridge-building project and was stabbed by a group of men who accosted him one day as he returned home. A footbridge whose construction was overseen by Mr Hickey was among the projects visited by Mr Ahern yesterday.
Six men were arrested and charged in connected with the killing. However, one of them, the son of a former military leader in Lesotho, obtained bail illegally and absconded. He is now believed to be living in South Africa, but is understood to have made several visits to Lesotho since, during which local police have failed to arrest him.
"You can't let people walk around the place if you are a known suspect for murder," Mr Ahern told reporters. "I made it absolutely clear that the Irish people don't forget these things."
He said the Lesotho Prime Minister knew all the details of the case and had discussed it with his attorney general last Friday.
It was likely that a trial of four of those in custody would proceed now, even while the man who absconded was still at large.