"If anyone has done anything wrong, appropriate action should be taken and the book should be thrown at them," Mr Perrottet told reporters on Tuesday.

It comes after an upper house inquiry heard allegations Liberal powerbroker Christian Ellis sought to branch-stack federal deputy leader Sussan Ley's electorate of Farrer in late 2020, in a ploy to take the seat for himself.

Ms Ley has called for Mr Ellis to be expelled from the party.

"It's incredibly damaging," she told Sydney talkback station 2GB.

"The premier is trying to win this state election (but) these factional bully boys are just making it tougher for him."

Mr Perrottet said the allegations tabled at the inquiry were being internally investigated.

"The Liberal Party will look at those matters and any wrongdoing that is found, if any, appropriate action will be taken," he said.

The premier's younger brother, Jean-Claude Perrottet, was the subject of an international search for a month as the same inquiry sought to call him for questioning about allegations of misconduct on Hills Shire Council.

The inquiry engaged professional process servers in a failed bid to locate him and other missing witnesses however Nine News published a photo of Jean-Claude on Tuesday, saying their journalists had found him in Sydney.

The upper house hearings concluded last week as parliament entered caretaker mode ahead of the March 25 election.

MPs were told various witnesses including Jean-Claude and Mr Ellis had gone to unprecedented efforts to avoid giving evidence, stifling their investigation.

When asked where Jean-Claude had been hiding, the premier deferred, saying, "that's a matter for him".

Mr Perrottet on Tuesday visited the key seat of East Hills to push the coalition's landmark offer to introduce a year of universal pre-kindergarten, saying $1 billion would be spent on building 500 new preschools on the grounds of existing schools.

It would mean 50,000 students able to access five days of free pre-kinder in the next four years.

Meanwhile, Labor outlined plans to cut 700 senior executive public service positions, allowing for savings to be put back into essential services.

It would also cap politicians' salaries for two years.

A 15 per cent reduction in executive jobs could be achieved through "natural attrition", shadow treasurer Daniel Mookhey said.

"This plan is based on natural attrition and we're not eager to rack up redundancy bills at the same time because that's a false economy," he said.

Under the coalition, senior executive roles had grown almost three times faster than the number of nurses, Mr Mookhey said.

Their salaries across government agencies, departments and state-owned corporations was about $1 billion a year and many top bureaucrats now earned more than $600,000 - nearly six times the average nursing wage.

Opposition Leader Chris Minns said there were more than 3600 senior executives across government, earning on average $272,000 - a 34 per cent blowout since the last term of government.

However Treasurer Matt Kean said the Liberal and Nationals were making the same commitment to reduce bureaucratic costs and pay.

"But, we will also go a step further by reducing the number of senior public servants by 20 per cent," he promised.

Australian Associated Press