New Zealand's Commerce Commission flagged competition concerns over Contact Energy's (ASX:CEN, NZE:CEN) proposed acquisition of Manawa Energy (NZE:MNW) ahead of a final decision next month, according to a statement Wednesday.

"[W]e are not currently satisfied that the Proposed Acquisition will not have, or would not be likely to have, the effect of substantially lessening competition in a New Zealand market," the Commission wrote in its Statement of Issues.

Regulators said the planned deal could disrupt competition in the supply of shaped hedges, which Manawa currently supplies to third parties. It is also concerned about the impact of the deal on the wholesale supply of physical electricity, which is already grappling with few industry players.

As such, the Commission extended the deadline for its final decision to March 31, with an option for a further extension. It also asked Manawa and Contact to submit their responses to its concerns by Feb. 21.

In a Thursday statement, Contact Energy said it will continue to assist the Commission in addressing the concerns, while reiterating that the proposed acquisition "remains compelling."

It also expects the deal to eventually obtain clearance, with the scheme of arrangement seen to be implemented by the first half of 2025.