Top NSW public servants are being asked how $250 million in council grants went out without any signed paperwork.

Senior advisers from NSW Premier Gladys Berejiklian's office are due to give evidence to the public accountability committee on Friday.

It comes after Finance Minister Damien Tudehope confirmed there are no signed approvals for 249 grants between June 27, 2018 and March 1, 2019 from the Stronger Communities Fund, which was established after council amalgamations.

Leader of the government Don Harwin was suspended from Parliament this week over a failure to produce documents showing signed paperwork relating to the grants.

Ms Berejiklian’s former chief of staff Sarah Cruickshank and her current senior policy officer Sarah Lau will give evidence. Ms Lau is tied in by emails, including on on June 28, 2018 which said: “The Premier has signed off further funding for metro councils. Outlined below is what is been approved”.

Reports say Ms Berejiklian directly approved more than $100 million in grants, but there are no formal records of her approvals, just emails from advisers.

Staff in Deputy Premier John Barilaro's office also appear to have emailed approvals, “funding of $600,000 to Edward River Council” mentioned in an August 2018 email.

But Mr Barilaro appears to be distancing himself from the fund.

“The Stronger Communities fund is not a fund that I administer. The Stronger Country Communities fund is something that I administer under my department in regional NSW,” Mr Barilaro said.

“There's an allocation made to every single local government area so it's not the beauty contest that we normally get, everybody gets a slice of the fund.”

Treasurer Dominic Perrottet said he is proud of the $252 million investment in local councils. He said he was not involved in deciding which councils received funding, but believes there would be “a very good reason” for them.

ICAC head Peter Hall QC has warned that the methods the government used in its administration of the council grants fund may open the door for corrupt conduct.

Non-government MPs have accused the government of using public money to bankroll its election campaign.