It could be dubbed the Slingshot law.

Consumer organisations have singled out the company while asking the Government to force phone and internet companies to a scheme designed to protect customer rights.

And the Government has signalled it is prepared to listen to rein in phone and internet customers that refuse to be accountable.

The Telecommunications Users Association of New Zealand and Consumer New Zealand wrote to Telecoms Minister Steven Joyce on Friday.

"TUANZ is fed up," said the organisation's business manager Katherine Hall. "We're fielding calls from disgruntled - mostly Slingshot - customers on a regular basis."

Hall said there was nowhere to direct customers of companies which did not belong to the Telecommunications Dispute Resolution Scheme.

The scheme is intended to be an option of last resort for frustrated customers who want independent arbitration. Membership is voluntary but includes Telecom, Vodafone and a host of other providers.

"Those who are signatories have smartened up their act and those who haven't have a licence to frustrate and annoy."

Slingshot is owned by Malcolm Dick and a number of private shareholders through its parent company CallPlus. The Herald on Sunday this week received its largest mailbag after a story about a customer being kept on hold for four hours over two days.

Dick said he disputed the claim that the most complaints came from Slingshot customers.

CallPlus chief executive Mark Callander also dismissed the claim. "It's just bullying tactics." He said a new framework for the TDRS meant the company could join it. He did not believe the present model was fair on members.

A similar scheme in Australia was compulsory for phone and internet companies. Joyce said he had told the industry he was comfortable with membership being voluntary "provided that all carriers are members".

"I advised them at the time that if they are not able to do this I will be considering a range other options."