* Shares rise as much as 5.7 pct above IPO price
* IPO was country's biggest since 2013, raised $537 mln
* Firm to invest $300 mln in new cement plant
* Government has pledged to raise infrastructure spending (Adds underwriter comment, political context)
By Neil Jerome Morales
MANILA, July 18 (Reuters) - The Philippines' second-biggest cement maker by market value enjoyed a strong stock market debut on Monday, as investors bought into a pledge from the three-week-old government to build roads, rails and ports to stimulate economic growth.
Cemex Holdings Philippines Inc's shares rose as much as 5.7 percent from the 10.75 pesos set in an initial public offering (IPO) that raised 25.13 billion pesos ($536.79 million) - the country's biggest IPO in three years.
The listing is the first since tough-talking Rodrigo Duterte became president promising to increase infrastructure spending outside of the capital Manila, to create jobs and ensure economic growth is felt more broadly throughout the country.
Duterte's election also coincided with emerging stability in the stock market after a year of excessive volatility that prompted some companies to defer listing plans. Market watchers said Cemex's strong debut may give those plans renewed impetus.
"You buy because you believe government investment will increase," said President Eduardo Francisco of BDO Capital & Investment, an underwriter for Cemex's IPO. "This signal here is the confidence in the Duterte administration."
That administration has pledged to raise infrastructure spending from 4 percent of gross domestic product last year to 5 percent this year and 5.2 percent next year. It has also pledged round-the-clock construction of infrastructure projects.
Among companies standing to benefit is Cemex, majority owned by Mexico's Cemex SAB de CV, one of the world's largest cement makers.
The Philippine subsidiary plans to use $300 million of the IPO proceeds building a factory with a capacity of 1.5 million tonnes of cement, to be in operation from the second half of 2019, said President and Chief Executive Pedro Jose Palomino.
Its IPO was the second-biggest in Southeast Asia this year after Fraser Logistics and Industrial Trust raised S$903 million ($669.73 million) in Singapore last month.
"They are listing at a good time because there's a lot of optimism in the market," said Head of Equity Investments Martin Enrile at BPI Asset Management. "Our market is rather at a pricey level but it continues to be driven by foreign inflows."
The main share index in the Philippines has risen - as in Vietnam - by 14.7 percent over the year to date. That gain is second only in Southeast Asia to the 15.8 percent of Thailand's benchmark.
The upward trend comes after a year of volatility amid speculation that U.S. monetary policy would prompt an outflow of foreign funds from emerging markets, among other factors. The volatility prompted several companies to delay IPOs, including Datem Inc, D.M. Wenceslao & Associates Inc and Pilipinas Shell Petroleum Corp - a subsidiary of Royal Dutch Shell PLC. ($1 = 46.8150 Philippine pesos) ($1 = 1.3483 Singapore dollars) (Reporting by Neil Jerome Morales; Writing by Karen Lema; Editing by Christopher Cushing)