By Reuters Staff (Adds detail, outlook) BANGKOK, April 28 (Reuters) - Thailand’s manufacturing production index (MPI) in March rose for the first time in 23 month, due to improved global demand and a low base effect, and is likely to increase again in April, the industry ministry said on Wednesday. The MPI’s rise of 4.12% from a year earlier was also its fastest pace in 29 months, although slightly below a forecast for a 4.4% increase in a Reuters poll. While a third wave of COVID-19 infections has slowed economic activity, the manufacturing sector has not been affected, ministry official Thongchai Chawalitpichaet told a briefing.