The BSA said the assertions made in the ad were opinion rather than fact.
A complaint against the National Party's "Let's tax this" advert has not been upheld by the Broadcasting Standards Authority.
National released the ad last week. It lists the taxes National claims will be introduced under Labour, and ends with the words "Let's tax this" - a parody of Labour's campaign slogan "Let's do this".
Jacinda Ardern has accused National of scaremongering over tax, saying many of the taxes listed in the ad would not be introduced under Labour.
The BSA ruling found the ad promoted the political opinions of National regarding Labour's policies, rather than making assertions of fact.
The Authority also considered whether the ad breached Election Programmes Code standards, which requires factual information to be clearly distinguishable from opinion or advocacy.
It was satisfied it would be clear to viewers that the ad was part of National's campaign.
"We consider it would have been clear to viewers that the advertisement did not contain factual information, but rather National's own analysis of Labour's comments, policies and tax announcements," the Authority said in its decision.
National leader Bill English and National's campaign ads have claimed Labour would increase income taxes, which Labour's Jacinda Ardern has rejected as "fake news."
While Ardern has said Labour will cancel National's take cuts, due to take effect from April next year, she has said Labour will not move on income taxes beyond that - and income tax will not be included for consideration by a Tax Working Group Labour plans to set up if in Government.
English said Labour would in effect be increasing income taxes because it would have to legislate to move the tax thresholds again. National had passed the legislation to change the tax rates in July as part of its Budget families package, although taxpayers will not see any change in their pockets until April.
"It's absolutely clear under National people on the average wage will pay $1000 less income tax than they will under Labour and Labour will have to change the current law to achieve that."
He denied that was a disingenuous argument or that there had been scaremongering on the campaign: "I think there's been pretty assertive questioning of policies all round."
He said Labour had "floated pretty vague policies" and should expect to be questioned.
National has in the past objected to Labour claiming National had "cut" health spending, saying it had put billions of dollars more into the sector. Labour's claims were based on health spending under National not keeping up with inflation and population growth since 2008.
English conceded some families would be better off under Labour's package, which included more generous Working for Families payments, but said people had to weigh that up against any new taxes they would have to pay such as an Auckland regional fuel tax.
"That's going to eat into the increase in the child payments under Working for Families. Voters are going to have to work that out."
He said National was not considering increasing fuel taxes over the next term.