Manukau City Council is calling for an official check on the competence of companies repairing leaky homes.
Councillor David Collings, who is an electrician, said the late 90s era of "hammer hands" replacing skilled tradesmen on building sites should not be repeated.
The state and council were each paying 25 per cent of the cost of fixing leaky homes but homeowners, who had little part except for choosing the benchtop, were paying the rest.
"Homeowners should have a guarantee their home has been built properly.
"Councillors are concerned that the builders and developers who have caused this debacle could come in and profit from the remedial work.
"We are asking that the Government has a process by which they vet those companies and individuals so that they will not be allocated any remedial work."
A vetting list should be drawn up from court records of respondents in leaky home cases and a test applied to confirm those fixing homes have a thorough understanding of weathertightness.
Home Owners and Buyers Association president John Gray said good builders who know how to do remediations were few and far between.
He said he was unsure about the fairness of any blacklist unless their liability had been determined.