National Legislative Assembly president Pornpetch Wichitcholchai on Monday sent the organic bill on the selection of senators to the Constitutional Court.
Mr Pornpetch said he had signed the petition submitted by 30 legislators requesting the court's ruling on controversial content in the bill.
The move followed a warning by chief charter writer Meechai Ruchupan of political chaos if the organic bills on the selection of senators and the election of MPs are declared unconstitutional. His warning came after the NLA passed the two bills.
The NLA decided to go ahead with the MPs bill, submitting only the one on senators to the court for a ruling.
The NLA president on Monday did not give details of the clauses in the organic bill his members want interpreted by the court.
He said last week that the concerns centred on provisional clauses allowing senate candidates to field themselves and also organisations to field candidates for selection and demand intra-group selection among candidates instead of cross-group voting.
This might contravene Section 107 of the constitution, which stipulates that senators must be installed through selections made by and among candidates, he added.
Mr Pornpetch on Monday expressed confidence that sending the legislation to the court would not delay the general election promised for February next year.
NLA whip Somchai Sawaengkarn said on Friday the court would probably deliberate the matter for no more than three months.
