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.
Kiwibank chief executive Steve Jurkovich said in a statement the bank, like all banks, is always considering the industries it should or should not be providing financial support to.
"These are a part of the choices we make as a bank.
"The policy we have introduced sets out our position on a number of sectors which we have determined may harm people or the environment.
"This aligns to our sustainability commitments and our purpose of making Kiwis better off. Like any policy we will continue to revisit its applicability and we are prepared to re-consider our position."
Jurkovich said he is more than happy to meet the appropriate government ministers to discuss the bank's position and will be contacting Jones directly today.