Business chiefs are paying up to $11,000 a head to receive policy briefings and meet with federal Labor shadow ministers in Sydney.
The two-day Federal Labor Business Exchange began on Tuesday morning and will run until Wednesday afternoon.
A business observer program was to be offered during the ALP national conference but the conference was moved to December when it clashed with the date of five by-elections.
The invitation describes it as a "unique opportunity to receive briefings on major policy areas and network" with shadow ministers.
The full price ticket is $11,000 while the discount price is $8250.
Labor has some repair work to do with the business sector following its opposition to company tax cuts.
Senior members such as Anthony Albanese are keen to rebuild bridges with small and large business ahead of the federal election due by May 2019.
Greens leader Richard Di Natale says Labor leader Bill Shorten should disclose the list of attendees in the interests of transparency.
"It is not good enough to say - trust us. If you have nothing to hide, then release the names of the participants," he said.
"It's not good enough for Labor to promise voters they'll prioritise essential services over big corporations, and then have cosy, closed summits with business leaders to shape their election platform."
A spokeswoman for the Commonwealth Bank declined to say whether employees were attending the program, but flagged disclosures would follow the rules.
"CBA discloses political events we attend as per commonwealth and state electoral agency requirements, so while I'm unable to confirm whether CBA will be attending the event at this stage, the information will be made available later in the year," the spokeswoman said.