People are having a very tough time tracking down Liberal members that have been called to appear at a NSW parliamentary inquiry.

A group of Liberal members, including the NSW premier's brother, have been sought to appear before a parliamentary inquiry investigating impropriety at the Hills Shire Council and property developers in the area.

However, despite engaging two private firms to deliver the summons, the members, Jean-Claude Perrottet (a Liberal factional figure), Christian Ellis (a former Liberal state executive member) and his mother, Virginia Ellis (Hills Shire Councillor and political staffer), could not be found.

The parliamentary committee stated that they were deliberately avoiding appearing before the committee.

A professional server was engaged to locate the members and spent over 17 hours searching in Deniliquin and surrounding areas.

On one occasion, Christian Ellis's wife was at home and was asked whether he was present, but responded that she did not know his movements.

A second private firm searched for the members in Sydney but was unsuccessful in locating them.

One member, Charles Perrottet, who was believed to be interstate, wrote to the committee and declined to participate, stating that he believed the inquiry to be partisan and defamatory.

The inquiry will resume on Thursday.