Air New Zealand is prolonging an offer of "compassionate" international discount fares to and from earthquake-stricken Christchurch as Australia operator Qantas faces criticism for sticking with normal pricing.

The New Zealand airline also last night announced that special $50 standby domestic fares to and from Christchurch would be available throughout next week until Sunday, March 6.

Although not all seats would be available at that price, as has been the case since Tuesday's earthquake, Air NZ said it would reduce Smart Saver fares between Christchurch and Auckland to between $69 and $149.

Smart Saver fares between Christchurch and Wellington will range from $59 to $129.

"Compassionate" international fares will continue to be available for people affected by the earthquake or immediate family members wishing to visit them in Christchurch, amounting to just $50 plus taxes for trans-Tasman and Pacific routes and $400 plus taxes for longer-haul travel.

Air NZ spokeswoman Tracy Mills said anyone who was in Christchurch at the time of the earthquake would qualify for those fares.

Sydney-based urologist Associate Professor Prem Rashid complained that it cost him $905 to return to Australia on a Qantas flight on Thursday, after he and colleagues at training meeting in Christchurch which was interrupted by the earthquake were flown to Wellington by the Air Force.

Professor Rashid praised the rapid response of New Zealand emergency services but said the Australian consulate failed to fulfil a commitment to help to get them home, and he was annoyed Qantas had charged him so much for rebooking his travel.

Mills confirmed that he would have been eligible for a $50 fare on Air NZ

Qantas spokeswoman Emma Kearns said that although her airline was not offering compassionate fares, it had put larger aircraft on its daily flights from Christchurch, for fares as low as $179 to Sydney.

But the lowest fares available yesterday through the Qantas website were $1090 for a flight today, $875 tomorrow and $980 on Monday.

The next $179 fare was not available for travel until Thursday.

Pacific Blue was offering fares from $399 for flights from Christchurch to Sydney today and tomorrow, reducing to $349 on Monday and $189 on Tuesday.

Although food supplies are reaching Christchurch, Consumer NZ said it had received one unconfirmed report of two-litre bottles of milk being sold in the city for $7.50c, about twice the normal price.

Deputy chief executive David Naulls said that although there was no price control on milk, and therefore no law was, he agreed with Earthquake Recovery Minister Gerry Brownlee that such a practice would be "morally reprehensible."

A spokesman for the minister said Mr Brownlee had not received direct evidence of price gouging, but was alert to the possibility in the aftermath of the earthquake.

The Contractors Federation is meanwhile inviting Cantabrians "needing piece of mind" in finding competent and qualified local professionals to assess the immediate safety of their properties to visit a one-stop website set up after the 7.1-magnitude earthquake which hit the region in September.

Chief executive Jeremy Sole said the website was a collaborative initiative of 21 national organisations launched amid concerns that quake victims were under threat from profiteering unqualified operators.