Labor will keep up its examination of issues around raids on Australian Workers’ Union offices as Senate estimates hearings continue.
It is understood senior minister Michaelia Cash will front the education and employment committee hearing.
The October 2017 raids on AWU offices shot to prominence when staff from the offices of two ministers – Senator Cash and former justice minister Michael Keenan – tipped off the media.
Camera crews and journalists beat the police to the Melbourne and Sydney sites.
The raids were launched in connection with decades-old donations made when Opposition Leader Bill Shorten was the AWU national secretary.
On Monday, the Senate committee heard Senator Cash and Mr Keenan twice refused to provide witness statements to police in relation to the media leaks.
AFP Deputy Commissioner Leanne Close said police wanted the opportunity to speak to both ministers and obtain a witness statement.
Instead, the ministers sent the AFP letters to explain their involvement.
Prime Minister Scott Morrison told parliament on Tuesday his ministers had co-operated with authorities.
Australian Federal Police believe evidence may have been destroyed in relation to the media leaks.
Senator Cash’s legal costs in the matter have come to $288,000 to date, according to attorney-general’s department figures.
The estimates committee will hear from officials of the Jobs and Small Business Department and Fair Work Commission, as well as the Registered Organisations Commission set up to investigate union misconduct.