Christchurch homeowners who bought houses with botched EQC repairs are taking the government agency to the High Court.

Because they didn't own the home at the time of the 2010/2011 earthquakes, the cost of repairs above EQC's $100,000 threshold won't be covered by private insurers.

Meanwhile, some homes are in need of repairs costing up to half-a-million-dollars.

However, EQC has denied it is shirking responsibility when it comes to the dodgy repairs.

Customer and Claims General Manager Trish Keith says insurance companies should pick up claims which are above EQC's limit.

"Wherever possible we do put things right, we're here for the long run. We want to put things right for the customers, we [have to] work to an act which has a cap limit of $100,000."

13 claimants have filed negligence claims against EQC thus far, and lawyer Andrew Hooker said it's just the tip of the iceberg.

"It's a national disgrace. It's an absolute scandal that EQC won't be accountable for the position they've put these people in."

A young Christchurch mother is among claimants taking EQC to the High Court, after unknowingly buying a home with botched repairs.

Georgie Hanafin and her partner bought their dream home in 2014 - and said it quickly turned into a nightmare.

"We spent $360,000 on the house and we've got a $330,000 mortgage. We had the house valued recently and if we were to sell it, it's worth $190,000 now."

Hooker said owners are filing negligence claims, as it was EQC who fuddled the repairs in the first place.

"They're saying to these people - 'we'll pay it up to cap, here's $100,000, now sorry you're on your own'. But then people are going to go - 'but it's going to cost me $ 400,000 to fix my house'. Oh well bad luck."