Ms Moroney said that she was happy with where the limits were set at present. But the increase in the road toll in recent years showed the limits of a harder stance on lower-level offending.
Over the past three years, New Zealand's death toll has risen steadily from 246 in 2013 to 312 last year.
Ms Moroney said she was driving between Hamilton and Tauranga on the weekend and saw a dangerous driver ignored by a police car, which pulled up somebody else on a minor infringement.
"I think the focus should go on the people who are well past the drinking limit, and well past the speeding limit as well.
"What we need to do is to make sure that the police aren't spending their time or resources pulling up people who are going two or three kilometres over the speed limit, while the dangerous driver continues on the road."
Associate Transport Minister Craig Foss said he found Ms Moroney's comments on lower-level drink-driving surprising, given Labour's support for the law change.
"Roads are safer, the culture of drink-driving has changed significantly. The road toll is still much, much too high. Much of it deliberate or beyond a normal accident - drugs, drink, excessive speed or fleeing from police or non constraints. So anything we can do to lower that road toll or the risks around it, we should be doing."
A total of 8155 lower-level drink-driving offences were handed out between December 1, 2014 and November 30, 2015.
Over the limit
251mcg-400mcg alcohol per litre of breath:
• Drivers caught under the lower drink-driving limit face a $200 infringement fee and 50 demerit points.
• If you accumulate 100 or more demerit points from driving offences in two years, you will be suspended from driving for three months.
Over 400mcg of alcohol:
• Maximum penalty for first or second conviction: three months imprisonment or up to $4500 and mandatory disqualification of at least six months.
•Third or subsequent offence earns disqualification for more than a year, a fine up to $6000 or up to two years in prison.