ANZ Group Holdings Ltd.’s A$4.9 billion ($3.2 billion) deal to buy Suncorp Group Ltd.’s banking arm was blocked by the Australian regulator.

The Australian Competition & Consumer Commission decided not to grant merger authorization for the acquisition, the regulator said in a statement Friday.

“We are not satisfied that the acquisition is not likely to substantially lessen competition in the supply of home loans nationally, small to medium enterprise banking in Queensland, and agribusiness banking in Queensland,” ACCC Deputy Chair Mick Keogh said in the statement.

The bank had agreed in July last year to buy the Brisbane, Queensland based firm’s banking operations in a bid to gain an edge over rivals. Competition has remained fierce in Australia’s mortgage market as interest rates rose over the past year.

“A substantial lessening of competition in home loans would have major flow-on impacts to Australians with a mortgage,” Keogh said. “More than a third of Australian households have a mortgage, with loans totaling around two trillion dollars, illustrating how critical it is that competition in this market is not substantially lessened.”

(Adds detail on size of acquisition in first paragraph, details throughout)