* PM Yingluck undermined by months of street protests
* Faces various court cases that could bring her down
* Economy is suffering, growth forecasts slashed
* But central bank not expected to cut rates again on Wednesday
By Amy Sawitta Lefevre and Aukkarapon Niyomyat
BANGKOK, April 23 (Reuters) - Thailand's Constitutional Court on Wednesday gave Prime Minister Yingluck Shinawatra until early May to defend herself against charges of abuse of power, delaying a verdict that could see her removed from office.
The charges relate to the transfer of National Security Council chief Thawil Pliensri in 2011, which opponents say was designed to benefit her Puea Thai Party. If found guilty, Yingluck could be forced to step down and some legal experts say the whole government would have to go with her.
Yingluck, who heads a caretaker government with limited powers, has been undermined by six months of street protests as well as various legal challenges against her, which have intensified since February.
Thawil was reinstated to his post in March but the Constitutional Court accepted a case brought against Yingluck by a group of 27 senators who petitioned it to rule that her removal of the security chief violated the constitution.
"The prime minister will be given until May 2 to present her defence and gather further evidence," Somrit Chaiwong, a Constitutional Court spokesman, told Reuters.
Any judgment that removes Yingluck will escalate tension between her supporters and the anti-government protesters. Some fear an increase in violence that could prompt intervention by the coup-prone military.
A long-running crisis broadly pits the mostly poorer supporters of Yingluck and her brother, former premier Thaksin Shinawatra, against the Bangkok-based middle class and the conservative establishment. Thaksin was ousted by the army in 2006 and has chosen exile rather than accept a jail term handed down in 2008 for abuse of power.
The protesters want to end Thaksin's political influence and set in motion broad political reforms that would prevent parties loyal to him from running for office again.
A Feb. 2 election was disrupted by the protesters, who stopped candidates from registering and blocked polling stations and the delivery of ballot papers. As a result, a court last month ruled the election void and the Election Commission has yet to set a new date.
The latest turmoil has dented tourism and depressed business confidence, causing the central bank to cut its economic growth forecast for this year to 2.7 percent. In January, it was expecting 3 percent and last October, before the protests flared up, it had forecast 4.8 percent.
The Bank of Thailand's monetary policy committee meets on Wednesday but, despite the economic gloom, is expected to leave interest rates unchanged after quarter-point cuts in November and March that took the policy rate down to 2.0 percent.
Despite occupying key government ministries for weeks at a time and bringing parts of the capital, Bangkok, to a halt until retreating to a city park in March, the protesters have failed to achieve their aim of bringing down the government.
They are now looking to the Constitutional Court and the National Anti-Corruption Commission (NACC) to remove Yingluck. Her supporters believe the courts and other state bodies are biased against her and Thaksin.
Amongst the charges she faces is one of dereliction of duty. She is the nominal head of a state rice-buying scheme that critics say is riddled with corruption and has run up huge losses.
The NACC, which brought that charge against her, is expected to deliver its ruling in May. If found guilty, she could be removed from office and may get a five-year ban from politics. (Writing by Amy Sawitta Lefevre; Editing Alan Raybould and Robert Birsel)
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