Premier Mike Baird is likely to be formally called to front a parliamentary inquiry into his contentious power privatisation plan, at which MPs plan to grill him over why an expert report on the proposal was altered following a phone call from his office.

Mr Baird on Sunday refused to say if he would appear before the proposed inquiry, the findings of which will determine whether Fred Nile's Christian Democratic Party supports the government's signature re-election policy: part leasing the state's electricity "poles and wires". The government needs the CDP's votes to pass the plan through Parliament.

Accused of interfering in a report that said the power privatisation plan would be "bad for the budget": Premier Mike Baird's office. Credit:Louise Kennerley

Reverend Nile would chair the inquiry's select committee, which has been expanded to nine members following complaints by the Greens that they had been excluded.

Four government MPs would sit on the proposed committee. Reverend Nile could form a majority with Labor, the Greens and the Shooters and Fishers Party – all of whom want Mr Baird to give evidence at the inquiry, including in relation to advice provided to the government by investment bank UBS.