Prime Minister Tony Abbott says he is "absolutely confident" the federal Liberal Party will not be dragged into the donations scandal engulfing the NSW Liberal Party, despite Speaker Bronwyn Bishop being contacted by the Independent Commission Against Corruption.

The commission has been examining the activities of the federal Liberal Party-aligned Free Enterprise Foundation, which is alleged to have been used to "launder" illegal donations and channel them back to the NSW branch of the party.

Tony Abbott in Epping on Sunday. Credit:AAP

Emails between a "private individual and a member of the Liberal Party" were tendered as part of a public exhibit on Thursday during the ICAC's inquiry into Liberal Party fundraising.

Commissioner Megan Latham ordered that the emails be suppressed after questions were raised about whether publishing them would breach parliamentary privilege.