DUBAI - Shares in Dubai Electricity and Water Authority (DEWA) surged about 20% on their market debut on Tuesday after its $6.1 billion initial public offering (IPO), the region's biggest since Saudi Aramco .

The utility's shares rose to 2.98 dirhams ($0.8114) in early trade, up from the IPO price of 2.48 dirhams per share.

Middle East and North African investment bank EFG Hermes said in a note to clients that it expects DEWA to be eligible for fast entry into FTSE's emerging markets index.

It estimates that DEWA can expect minimum inflows of $53 million from FTSE passive trackers and any increase in price would lead directly to more inflows.

As well as raising money for Dubai, the IPO aims to help the emirate's exchange to compete more effectively with bigger rivals in the region, such as those in Saudi Arabia and Abu Dhabi.

DEWA said in its prospectus that the 18% share sale by the Dubai government was aimed at boosting trading liquidity in the stock market and raising the company's profile with international investors.

The public share sale is the biggest for Dubai and the largest across the region since Saudi Aramco's world record $29.4 billion IPO.

($1 = 3.6726 UAE dirham)

(Reporting by Hadeel Al Sayegh Editing by David Goodman)