Singapore has long ruled the region's booming venture capital and private equity investment market, but new players are emerging that could take its crown.

Indonesia and Vietnam are the most likely challengers.

A Bain & Company survey found that around 90 per cent of investors said the two nations would be the hottest South-east Asian markets outside of Singapore over the next 12 months or so.

The number of firms in Indonesia raising first round of funding last year rose more than 300 per cent from 2012. And Indonesia and Vietnam generated 20 per cent of the region's private equity deal value over the past five years, and that percentage is likely to grow, said Bain.

What is abundantly clear is that the pie is growing fast with deal value set to soar to US$70 billion (S$96 billion) over the next five years, double that of the previous five years, a separate Bain report said yesterday.

The report also predicts that the region will produce at least 10 new unicorns - start-ups that rapidly achieve market valuations of US$1 billion or more - by 2024.

Scores of new investors have been pouring into the region, attracted by strong macroeconomic fundamentals, the chance to invest in emerging regional champions and a deepening secondary market for deals of all sizes.

The mix includes a combination of local venture capital funds and private equity operators, sovereign wealth funds and global funds.

Technology companies have attracted the bulk of new capital, rising to 40 per cent of deal count last year from 20 per cent in 2014.

Since 2012, 10 unicorns, including Grab, Go-Jek and Traveloka, have created a combined market value of US$34 billion, ranking South-east Asia third in the Asia-Pacific region, behind China and India.

Strong investor interest in the region's developing technology sector and other consumption-based industries is likely to help sustain higher levels of investment.

Bain senior adviser Suvir Varma and principal Alex Boulton, authors of the first report, expect the sector to contribute 20 to 40 per cent of deal value over the next five years, particularly the financial technology sector.

They added that investor interest in healthcare and education, "sectors with significant long-term growth potential, but traditionally fragmented", will also redouble.

For now, "investing in South-east Asia is taking off, but new challenges - notably intensifying competition and rising valuations, which are at their highest level in a decade - will require investors to tread carefully", said Mr Boulton.

Therefore, "skilled investors must raise their game to continue producing strong returns in what is still an evolving market", added Mr Varma.

The Bain report also noted that government initiatives have played a key role supporting venture capital and vibrant start-up centres.

Singapore's Startup SG Founder programme, for example, provides $3 in matching funds, up to $30,000, for every dollar new entrepreneurs raise. Firms seeking to raise a second round of $2 million to $4 million receive $1 in matching funds for every dollar they raise.

In October last year, the Monetary Authority of Singapore further simplified the authorisation process for venture capital managers to help support start-up and growth-stage businesses.

These moves and others have helped boost the percentage of Singapore-based start-ups that receive follow-on funding to the same level as start-ups in Europe, Bain said.

Governments throughout South-east Asia are pursuing similar policies.