July 16 (Reuters) - Medical device maker Masimo Corp ( MASI )

said on Tuesday it has filed a lawsuit against Politan

Capital in a California federal court, seeking to force the

activist investor to correct "material misstatements and

omissions" in its proxy materials.

Quentin Koffey-owned Politan has long criticized Masimo's ( MASI )

capital allocation and board oversight and expressed concerns

about the California-based company's $1 billion purchase of

consumer audio products maker Sound United.

Politan has a near 9% stake in Masimo ( MASI ) and has nominated two

candidates to be elected to the company's five-member board.

Only two board seats will be voted on this year.

It is the second time in two years that Politan has proposed

board candidates. Last year, Masimo ( MASI ) shareholders elected

Politan's two suggested directors, including Koffey.

Politan said there were "no misstatements" and the lawsuit

by Masimo ( MASI ) was "completely without merit".

Earlier in the day, Masimo ( MASI ) had postponed its annual

shareholder meeting to Sept. 19 from July 25.

The activist investment firm criticized Masimo's ( MASI ) decision to

delay the meeting, calling it a "last-gasp attempt" to prevent

shareholder voices from being heard.

Politan said it will take all necessary actions to ensure

the annual meeting is not delayed further.

Masimo's ( MASI ) stock price has fallen 27% in the past 52 weeks.

Politan has said it would immediately review strategy, costs and

plans for growth if its candidates are elected.

Proxy advisory firms ISS and Glass Lewis have recommended

Masimo's ( MASI ) shareholders should vote for Politan's candidates -

William Jellison and Darlene Solomon.