Green Party co-leader Russel Norman is calling for the Government's accounts to be shifted from Westpac Bank to KiwiBank.
Dr Norman said on Saturday the party is serious about fixing the banking system so New Zealand is no longer 'a mortgage slave' to Australian banks.
He said the big banks wield enormous influence within New Zealand and the last two Governments have been unwilling to challenge that.
Dr Norman told the party's annual meeting that the Green Party would, over time, move the Government's banking contract to KiwiBank.
He also suggested that state-owned energy companies issue green energy bonds to raise capital.
Dr Norman said many New Zealanders are looking for a safe place for their savings, since the collapse of so many finance companies.
He said public energy companies, funded by Kiwi mums and dads with safe green energy bonds, could create a vision for a bright future.
Party members discussed, in a closed session, how the party should position itself politically after the election with an announcement due on Sunday.