UDC is potentially on the block as part of ANZ’s strategy to review its focus on where it allocates capital and resources.

The trade finance unit had total assets of $2.4 billion in the 2015 financial year.

A spokesman said: “We explore various strategic options from time to time, although this does not mean they will be sold. However it remains very preliminary and no decisions have been made. It’s business as usual for UDC staff, customers and investors. If ANZ was to make a decision regarding a potential sale of UDC Finance, we would inform staff, customers and investors immediately.”

But Massey University banking expert David Tripe said the move was consistent with what ANZ had been doing over recent times. “They’re getting back to a focus on their core banking business.”

He said Heartland, one of the parties interested in buying the business, might struggle to raise the capital to do so. It might require a share issue or a joint venture with another party, Tripe said.

UDC is a bit smaller than Heartland but more profitable.

Macquarie was another possible purchaser, he said. "Because it is so large in the New Zealand market it will be harder to find purchasers."

Other analysts said a private equity buyer could have an advantage of Heartland because it would not be bound by capital adequacy ratio requirements that apply to banks, reports said.