JAKARTA, Feb 27 (Reuters) - Indonesia's Riau province declared a state of emergency on Thursday as haze from raging forest fires, often deliberately set, disrupted flights and marine navigation and authorities reported a sharp rise in respiratory problems.
The national disaster mitigation agency said the province of 5 million, a major palm oil growing region, had been experiencing haze for several weeks due to illegal land clearing and prolonged dry weather.
"According to the data we have, the fires have gotten worse and need to be extinguished with water-bombing planes and we are ready to do that," Sutopo Purwo Nugroho, spokesman for the disaster mitigation agency, said in a text message.
Reuters TV images showed smoke rising from swathes of burning land as firefighters struggled to contain the blazes, complaining of limited equipment and water supplies.
Provincial authorities handed out masks and urged residents to stay indoors.
"The situation is worrying...because we have seen an increase in cases of respiratory problems from 5,000 in January to 22,000," Zainal Arifin, head of the provincial health department, told reporters.
Several flights were cancelled or diverted from airports in Riau as visibility dropped to less than 1 km (half a mile), the disaster mitigation agency said.
The Indonesian Palm Oil Association told Reuters that haze had caused delays to shipments from airports and ports in neighbouring North Sumatra province, but give no details.
Haze is a recurring problem for Indonesia and its neighbours, often caused by farmers and companies burning forests to make way for palm oil plantations.
President Susilo Bambang Yudhoyono had to apologise to neighbours Singapore and Malaysia in mid-2013, when those countries were blanketed with thick smog from forest fires in Indonesia.
Analysts estimated last year that Singapore faced nearly $1 billion in financial losses in what was Southeast Asia's worst air pollution crisis in 16 years.
The Indonesian meteorology agency said winds were moving in a southwesterly direction, away from Singapore. But a shift in wind direction, which usually occurs near the end of the Indonesian monsoon season in April or May, could affect the city-state again.
Police arrested 26 people last week in connection with fires and illegal land clearing, which have affected about 2,000 hectares (5,000 acres) of land.
(Reporting by Kanupriya Kapoor and Yayat Supriatna, Editing by Ron Popeski)