The Earthquake Commission (EQC) says it will take on extra staff to help pay outstanding invoices on its books.
The Amalgamated Workers Union says delays in EQC payments for housing repair work in quake-hit Christchurch are building to a crisis point.
Canterbury has been hit with two damaging quakes recently - on 4 September last year followed by and the fatal quake on 22 February.
Some employers have not been paid for several months and therefore are unable to pay their employees, nor for the materials they used, the union says.
On Monday afternoon Prime Minister John Key said he wanted the payments made as fast as possible. Mr Key says his advice is that of 28,900 invoices, the Earthquake Commission has not paid 10,000.
However, EQC chief executive Ian Simpson told Checkpoint on Monday that only 1000 payments are deemed to be overdue.
Mr Simpson says at present, 25 people are in the team based in Wellington and the agency is looking to add another 25. He expected the last of the payments to be made by sometime in July.
The Labour Party says the Government should require EQC to pay for work related to the quakes as quickly as possible.
Leader Phil Goff said it is essential for the Christchurch economy for tradespeople to be paid and the Government needs to address the situation if there are delays.
Union members advised to stop repair work
Amalgamated Workers Union spokesperson Calvin Fisher says he has advised some members to stop doing quake repair work until they are paid.
Mr Fisher warned work to weather-proof houses and bring down dangerous chimneys may be compromised if payment is not made.
He told Nine to Noon earlier on Monday he believed the volume of repair work invoices has been swamping the Earthquake Commission and it does not have enough staff to process them.
Glazier Darren Cranfield says he is still waiting for payment from EQC for work done by his company after the 4 September quake.
Mr Cranfield told Nine to Noon it has taken the EQC months to contact him about the $54,000 amount.
However, EQC says that when everything is in order with contractors' invoices, it makes payment within 21 days of their receipt.