"You'll get what you deserve in the end if you just sit back and wait for it to happen," the voice says.
McCaw then gets up and runs forwards and the ad's message hits us.
"But if you just sit back and wait for it to happen, you get what you deserve in the end. You'll live a life of what ifs ...
"You don't need to take it easy. It's time."
A statement from Westpac said the campaign came about after research showed Kiwis were great at setting financial goals and then never making them happen.
The McCaw ads would "encourage New Zealanders to find time and take action".
The bank says he will appear in "a number" of videos, where he will discuss what might have happened if he'd listened to his excuses, fears and concerns.
McCaw said many Kiwis say "should've", "could've" or "going to", but sometimes they needed to make it happen. This was a mantra he lived by, he said.
"I think retiring was like finishing one chapter and opening a new one. I'm now in a position where I can seize opportunities I haven't been able to try in the past.
"It's time to do the other things that I've always thought about doing or wanted to do. Now, I'm setting about making those happen. It's exciting to set goals, go for them and achieve them. That is whether it's a physical goal, visiting somewhere you've always wanted to or saving for something that means a lot to you personally."
McCaw posted the video on his Facebook page this morning, asking his more than 492,000 followers what they thought.
"It's brilliant! The ad demonstrates the ability to show unwavering determination, with a bank who is prepared to support you on your journey, whilst incorporating a beautiful landscape. Clever ad campaign!" said one Facebook user.
"Hey Richie, you can run backwards pretty good," said another.
Westpac's research showed 97 per cent of New Zealanders have a short-term personal finance goal and 95 per cent a long-term one, but a lack of time and procrastination were getting in the way.
"While it's great that Kiwis are focused on both short- and long-term financial goals, we are concerned many are not achieving them," said Andrew Kerr, Westpac's marketing, products and transformation general manager.
The bank said it chose McCaw to front the campaign as he would instil confidence.