* Court sends case over $3.7 bln deal back to lower court
* Ecologists say ruling lifts investment ban
* PGE has no comment on project relaunch
(Adds environmental group comment, share reaction)
By Maciej Onoszko
WARSAW, Oct 2 (Reuters) - A Polish court ordered the re-examination of a block on a 11.6-billion zloty ($3.7 billion) power investment by utility PGE in a setback to environmentalists opposing the project.
The project, keenly awaited by local builders, has been shrouded in uncertainty since PGE had to delay the construction of two 900-megawatt coal-fired units after a court blocked the investment following an appeal by ecologists.
The ruling on Tuesday sent the case back to a lower court.
Environmental group ClientEarth, which has been opposing the plan, said the verdict allows PGE to restart the project, but Poland's top utility would not say whether it would do so or wait for final court clearance.
The utility previously said more delays in starting the project in the southwestern city of Opole could hurt Polish construction firms, and deprive the slowing economy of an important cash stimulus.
Poland's construction sector is following the case closely as many major builders - strapped for cash after bidding for road deals pushed them to the brink of insolvency - are involved in the project.
The consortium to build Opole includes Polimex , Rafako , a unit of PBG , and Mostostal Warszawa , which is the Polish unit of Spanish firm Acciona .
PBG has been in bankruptcy protection since June, while Polimex has until Nov. 24 to come up with an austerity plan after its creditors agreed to waive interest on the group's 2.5 billion zloty debt pile in July.
Shares in were up 0.11 percent at 0853 GMT, while Polimex and Rafako fell 3.33 and 1.04 percent, respectively, and Mostostal remained flat.
($1 = 3.1733 Polish zlotys)
(Writing by Adrian Krajewski; Editing by Louise Heavens and Hans-Juergen Peters)
Keywords: PGE COURT/