Shane Jones is questioning why Kiwibank ruled out doing business with companies that deal with the extraction, production and manufacturing of coal.
The New Zealand-owned bank launched a responsible business banking policy this month, and says it will no longer accept clients who, in their opinion, run businesses that do harm.
That includes companies dealing in tobacco, palm oil, casinos, predatory lending, adult entertainment, synthetic drugs and weapons.
Although Kiwibank has now indicated that it will drop the ban on brothels and strip clubs.
Shane Jones is the Associate Minister for State Owned Enterprises.