48. Do political parties have to report on their election campaign finances?

"206I Return of party’s election expenses
(1) Within 90 working days after polling day, a party secretary must file a return of
the party’s election expenses with the Electoral Commission.
(2) The return must be—
(a) in the form required by the Electoral Commission; and
(b) accompanied by an auditor’s report obtained under section 206L.

206IA Return of party’s allocation expenses
(1) Within 90 days after polling day for a general election, a party secretary must
file with the Electoral Commission a return of expenses incurred by the party
that have been funded from the party’s allocation.
(2) The return must be in a form approved by the Electoral Commission and include
details of—
(a) the amount of the party’s allocation; and
(b) all accounts sent by the party to the Electoral Commission under section
80B(1) of the Broadcasting Act 1989 in respect of the expenditure of the
party’s allocation.
(3) The return must be accompanied by an auditor’s report obtained under section
206LA."

Section 206I and 206IA, Electoral Act of 1993. 

See also Sections 206H and 206O

"206H Invoice and receipt required for election expenses of $100 or more
Every payment made in respect of any election expenses of a party, other than a
payment that is less than $100, must be vouched by an invoice stating the particulars
and by a receipt.

...

206O Obligation to retain records necessary to verify return of party’s election
expenses
(1) A party secretary must take all reasonable steps to ensure that all records, documents,
and accounts that are reasonably necessary to enable a return under section
206I to be verified are retained until the expiry of the period within which
a prosecution may be commenced under this Act in relation to the return or in
relation to any matter to which the return relates.

(2) A party secretary who fails, without reasonable excuse, to comply with subsection(1) commits an offence and is liable on conviction to a fine not exceeding $40,000."

Parties must file returns on their election expenses and on their allocation expenses.