In a follow-up interview with the Herald, father-of-three Rook said he stood by his comments but regretted his choice of words.
"I just wanted to know who was responsible for leaving presenters on air and at what stage of their pregnancy? I'm old fashioned. When a woman gets to that stage of pregnancy [show] a bit of decency - stand her down," he said.
The 69-year-old later apologised and admitted he was "out of touch".
Clarkson took to Facebook to discuss her reasons for staying on air, and to thank those who had supported her decision to stay in front of the camera.
"To those who have chosen to write in support of me and my twins, thank you. As a heavily pregnant woman I struggle with my own demons about my body changing shape but I choose to stay in front of the camera to encourage others to be proud of the job that we are doing - creating life," she wrote.
"It is a major privilege to carry and create a human being and in my case two. Just like it is a privilege to enter into your living rooms each weekend. Thank you once again for your show of kindness - nga mihi ki a koutou katoa."
On Twitter, Wright retweeted messages of support with thank you notes.
A TVNZ spokesperson said it was Clarkson's choice how long she stayed on air.
"We're thrilled for Jenny-May. TVNZ is fully supportive of women working during pregnancy and supports their return to work. Like a lot of Kiwi women, Jenny-May is working during her pregnancy. She's not the first and she won't be the last member of our news team to do so.
"As well as her One News duties, she's currently filming segments which explore pregnancy for TV One's lifestyle series Whanau Living. Jenny-May's a talented and professional broadcaster. It's her choice to decide at what point she takes a break from her role and we'll support her decision 100 per cent."
Rook sparked the debate with his letter that said Clarkson wasn't in a fit state to be presenting the news.
"Who is responsible for allowing a sports reporter in a very pregnant state to remain on screen?" he wrote. "I have no problem seeing pregnant women in normal situations or places, but to have them remain on TV in a state which I feel is embarrassing and an eyesore? It's time to replace them.
"So please, TVNZ, open your eyes and show some common sense. "As for the presenters themselves, I wish them all the best for their new arrivals."
The letter was posted on Twitter by The Spinoff's Alex Casey, along with the comment: "Very cool guy of the week."
It sparked outrage, and many backed Clarkson and Wright.
In an interview with NZ Herald, Rook said he had no problem with the pregnant female form - he was simply trying to ask what the cut-off point was for pregnant TV presenters being on screen.
But he admitted he'd chosen his words badly and regretted writing the letter.
"I shouldn't have said, 'It looks embarrassing and it's an eyesore' - I wish her well. We've gone through childbirth and it's the best thing on earth. All I wanted to know was, who was responsible at TVNZ and at what stage they should stop presenting on screen?"
He also admitted he was "out of touch" and wasn't expecting the avalanche of abuse he had received since his letter was posted online.
"It's becoming a slanging match. They're talking about having pregnant women coming on my front lawn with placards. That's a bit silly. I'm 69 and obviously I'm out of touch with all this sort of carry-on."
TV Guide said the letter had sparked a "huge response" and backed Clarkson remaining on screen.
"Here at the TV Guide, we believe Jenny-May Clarkson is an excellent sports presenter and the fact that she's pregnant has no impact on her ability to do her job," the magazine posted on Facebook.
The Equal Employment Opportunities Commissioner said pregnant women were protected by law.
"This should be one of the happiest times of their lives and thankfully for most women it is a positive experience for both employer and employee which extends to work colleagues, customers and those they interact with."
- nzherald.co.nz
