"Shooting on Thursday and Friday was pretty dreadful.
"Nigella is fantastic, very professional and she handled it well."
Communications company Assignment Group co-founder Kim Thorp said the weather had been a bit of a challenge, but he was sure Hawke's Bay would still look good in the commercial.
After the high publicity of Ms Lawson's book tour, Mr Thorp said they had worked hard to keep her visit to the Bay under wraps.
As they were doing some "pretty complicated shoots" the commercial was kept very low-profile.
"She was there purely to work," Mr Poole said.
He said Ms Lawson had been working hard and didn't have a lot of spare time to sightsee.
But on Saturday she did have a chance to look around Hawke's Bay, and had visited several restaurants.
One of these was Elephant Hill, where Ms Lawson and a group of around 15 enjoyed dinner in the barrel cellar on Friday evening.
On Sunday the celebrity chef tweeted a landscape photo overlooking hills, writing: "Beautiful Hawke's Bay! Beautiful wine, too".
Ms Lawson flew to Auckland on Sunday evening where she bumped into Auckland Central MP Nikki Kaye.
Ms Kaye tweeted a picture of her and Ms Lawson at Auckland Airport, and wrote: "Bumped into the very lovely [Nigella Lawson], such a warm, genuine and smart woman who has a real affection for NZ."
Ms Lawson flew out of the country on Sunday evening.
She has shot numerous Whittaker's commercials since being signed by the company in 2012.
The tour for her new cookbook, Simply Nigella, began in Melbourne on January 18, and ended in Invercargill on January 26.
The cookbook is her 10th - her first, How to Eat, was published 18 years ago.
Later this year, Simply Nigella will be accompanied by a six-part, prime-time TV series on the BBC.