Nats won't contest NSW by-elections

The NSW Nationals says it won't run candidates in by-elections forced by the resignation of two disgraced state Liberal MPs.

Voters in two NSW seats vacated by disgraced Liberal MPs will go to the polls on October 25. (AAP)

The NSW Nationals won't contest by-elections brought about by the resignation of two disgraced Liberal MPs.

Newcastle MP Tim Owen and Andrew Cornwell, who represented Charlestown, quit politics last week after confessing at the Independent Commission Against Corruption (ICAC) to receiving banned donations from property developers.

In a statement issued on Monday night, the NSW Nationals said they "will not be contesting either seat."

Liberal state director Tony Nutt says his party won't field candidates as "an explicit act of atonement".

The by-elections are due to be held on October 25.

Both seats have traditionally been held by Labor and are expected to return to the ALP.

The by-elections are expected to cost taxpayers about $1 million.