The least-developed nations may offer interesting opportunities for investors seeking “tomorrow’s emerging markets,” according to Templeton Asset Management Ltd.’s Mark Mobius.

Templeton has opened offices in Vietnam and Dubai in the last few years to take advantage of “exciting opportunities” in Southeast Asia’s Mekong River region and so-called frontier markets in the Middle East, Executive Chairman Mark Mobius said in a report. Slovenia, Romania, Croatia, Kazakhstan and Ukraine are also starting to show promise, he added.

“Frontier markets are looking interesting and could become tomorrow’s emerging markets,” Singapore-based Mobius wrote in the report, which was posted on Templeton’s Web site today.

The MSCI Frontier Markets Index, which tracks stocks in nations from Vietnam to Serbia, has gained 15 percent this year. That’s lagged behind a 57 percent rally in the MSCI Emerging Markets Index and a 21 percent advance in the MSCI World Index.

Romania’s BET index and Kazakhstan’s eight-stocks KASE benchmark both rose to the highest in almost a year. Romania’s index jumped 1.4 percent Friday while the Kazakhstan gauge climbed 0.7 percent, with both at the highest level since Sept. 29, 2008.

Emerging markets have become increasingly significant alternatives for global investors because they offer “potentially higher returns,” said Mobius, who oversees about $25 billion.

Portfolio inflows into emerging markets have totaled more than $123 billion since 1995, even after the financial crisis last year saw withdrawals of $49 billion, the investor said. More than $44 billion have since returned in the first seven months of the year, he added.

Investors should adopt a “positive long-term view” of these assets because of developing nations’ economic growth, consumer spending and the accumulation of foreign exchange reserves in these markets, Mobius added.