Large catches are being hauled in from South Westland rivers, although locals remain secretive about exactly who is getting lucky striking the "wriggling gold" and where.
Department of Conservation ranger Charlie Boulton said there had been several "genuine" reports from whitebaiters around Haast of catches weighing "well in excess of" 100kg.
Fishing conditions had improved dramatically last month after a dismal start to the season, he said.
Most whitebaiters were "more than happy" with recent catches. He declined to say which rivers were proving to be hot spots for the delicacy.
"Hell, if I was to say one river was running better than the rest I'd get shot," he said.
Supply companies Westbait and Curly Tree Whitebait are paying between $40 and $50 a kg for the fish.
A Cascade Whitebait Co spokesman would not discuss how much whitebait the company was buying from fishermen.
He did not want to talk about catch sizes for fear of attracting more punters seeking the elusive sprats.
"All it does is draws a whole lot of people to the Coast, which you don't need," he said.
Hokitika River whitebaiter Peter Campion, who has fished the stand closest to the Hokitika bridge for about 12 years, said late-season catches had been "patchy", although it had improved over the past few weeks.
"It's a game of chance. If your net's not out, then you're not in," Mr Campion said.
The Greymouth Star reported this week whitebaiters armed with scoop nets had packed the Hokitika River mouth amid reports a catch of 100kg was hauled from the mid-channel on Sunday, while a stand further back took a massive 300kg off one tide.
West Coast Whitebaiters' Association president Des McEnaney said he had not heard of any bigger hauls since then.
"Overall, it [the season] hasn't been brilliant, but we still have some time left."
The 2010 season closes on November 14.
- Additional reporting Greymouth Star
