Maintaining New Zealand's Covid-19 restrictions drew some police resources away from focusing on road safety targets, says Assistant Commissioner Bruce O'Brien.
The Road to Zero targets aim for a 40% decrease in deaths and serious injuries by 2030 compared to the 2018 toll.
An annual monitoring report looking at the safety strategy has found the police fell short of expectations.
Last year 320 people died on the roads, while 2323 people were seriously injured - numbers dubbed "unacceptably high" in the report.
The report is jointly released by Te Manatū Waka - the Ministry of Transport, Waka Kotahi and police.
Police were shown to have completed just half of the expected breath tests throughout the last year, and while road policing staff numbers appeared high, the report notes many were pulled away from the road to cover Covid-19 issues.
Police assistant commissioner Bruce O'Brien told Morning Report this year's outcomes were "looking extremely concerning".
"We're well aware of that, we're holding ourselves to account..."
O'Brien said police resources in 2021 went into the Covid-19 response strategy.
Police had a challenging year and were distracted manning borders in Auckland, supporting MIQ and the health restrictions, he said.
"So that played one part of it but we do acknowledge that we do have work to do in increasing our performance in impairment testing and as an organisation we're fully committed to do that."
The road to zero strategy was an all system approach, he said.
"It's going to take all agencies to play their part infrastructure and speed management are components of that, as is police enforcement and prevention."
But he said the driving public also needed to play their part.
O'Brien said it was not a funding issue and people could expect to see more police acting on drink driving and speeding.
National's transport spokesperson Simeon Brown said the government's focus on vehicle emission standards was overshadowing safety and it had been too focused on clean cars.
He told Morning Report while lowering emissions was important, it couldn't be at the expense of safe cars.
"Of course increasing the cleanness of our vehicle fleet is important but that can't be done by itself it also needs to be done alongside making sure that new cars or cars coming in are actually safe as well."
He said a number of the key targets hadn't been met and breath testing target was "an abysmal failure".
"There's some serious issues in this report that need to be addressed and we're calling on the government to focus very much on those."
Safety issues like potholes were not being measured by the report, Brown said.
"The reality is, it's not just about making our roads safer you've got to also invest in the new roads that actually make those big significant differences as well. We've seen an absolute gutting of the national land transport find when it comes to actually building new infrastructure alongside making sure we're maintaining the roads."
Te Manatū Waka Road to Zero director Bryan Sherritt said "we can do a lot better", especially compared to the performance in other jurisdictions.
Deaths and injury rates in New Zealand were about twice as high as the best performing states in Australia, and three times the highest performing countries in Europe, Sherritt said.
He agreed with the assistance police commissioner that an all of system response was needed.
He said car technology was improving but New Zealand wasn't replacing its fleet as fast as other countries.
One of the focus areas of Road to Zero strategy was vehicle standards and the ministry was currently doing work on this, he said.
Road infrastructure was also a key focus. "What we need to do is increase the numbers or length of road that have those road safety features".
Sherritt said this was something that took time.