Multiple South Island businesses are reporting Eftpos outages on Monday.

Invercargill City Council said it could only accept cash payments at its main office and facilities or payments through its online portal.

Supermarkets and pharmacies were also affected.

Electronic payment provider Paymark said a fix was implemented earlier on Monday morning but it was still receiving reports of Spark-connected Eftpos users having connectivity issues.

"We are actively investigating a widespread connectivity issue between Spark and Paymark that is impacting terminal connectivity to the Paymark network," the company said.

"We are working closely with Spark and relevant parties to restore normal connectivity as soon as possible."

Eftpos New Zealand confirmed customers connecting to its network were not impacted.

RNZ has contacted Spark for comment.