Vicha Mahakhun, spokesman of the National Anti-Corruption Commission (NACC), said the independent body has sufficient evidence to charge the two for intentionally violating the Constitution.
The NACC will summon them to acknowledge the allegation on January 10, he said.
The complaint lodged with the NACC involves 381 other members of the House of Representatives and Senate who were simultaneously charged with dishonestly performing their duties in proposing and passing a bill on the composition of the Senate.
Mr Vicha said the NACC has questioned six witnesses and requested relevant documents from the Constitution Court, parliament and complainants.
The NACC will wrap up its investigation and decide on the fate of 381 legislators on January 7, he said.
The Constitution Court earlier ruled against the ruling Pheu Thai Party’s proposal to revise the charter to change the composition of senators.