Robertson said Luxon was now "spinning" his position after the National leader said in statements he would not seek to change abortion laws in New Zealand.
"We know what Jacinda Ardern's position is here, and we know what Christopher Luxon's is," Robertson said.
He said he understood why people might be sceptical of Luxon's assurances that the topic would not be revisited given his personal views.
Robertson said there had been a growth of bigotry and racism in many parts of the world.
He said he believed New Zealand was in a "good place" but that people needed to continue to stand up to these issues.
Roberston said he'd seen an increase in threats to himself and others. There had been an increase even since the occupation at Parliament in February, he said.
Referring to an incident in Dannevirke involving Robertson being verbally abused, he said police were present and he believed the person had been spoken to.
Robertson this morning told Newshub he thought Luxon needed to make his view on abortion clear, pointing to a comment in 2021 that he believed abortion was akin to murder.
"He managed to put out two statements in two days over the weekend and previously he's said that abortion is akin to murder," Robertson said.
"Mr Luxon might be saying convenient political things now, I think people know where he really stands and obviously people will judge on what he says as well as his actions."
Robertson told Newshub Luxon needed to be clearer about how exactly he would ensure the topic would not be revisited.
In response, National deputy leader Nicola Willis, who is pro-choice, said the party was being "crystal clear" that these laws would not be "relitigated or revisited".
She said Labour was creating "needless anxiety" by stirring debate.
"I actually think that these attempts by Labour to import US style culture wars into New Zealand is irresponsible. It is creating needless anxiety."
Ardern said shortly after the US ruling it was a "loss for women everywhere". She said people were "entitled to have deeply held convictions on this issue".
"But those personal beliefs should never rob another from making their own decisions."
Aid to Ukraine
Robertson said the latest $4.5 million in funding demonstrated support for Ukraine and acted in accordance with international partners.
Asked about today's Ukraine support and how it may influence the free trade talks with the EU, Robertson said those talks were separate issues.
A statement said deployments of New Zealand Defence Force (NZDF) intelligence, logistics and liaison officers in the UK, Germany, and Belgium were also being extended.
Further support included for the International Criminal Court (ICC) investigations.
"Russia's continued assault on Ukraine is a blatant attack on innocent lives and the sovereignty of another country," Ardern said in a statement.
"Our response has not only included the condemnation of Russia's actions, but practical support for Ukraine."
The support comes on top of previous diplomatic, humanitarian, legal and military aspects of the conflict which total more than $33 million of assistance to date, Ardern said in the statement.
Trade and economic sanctions have also limited Russia's ability to finance and equip the war, she said.
Robertson said personnel that returned yesterday on the Hercules aircraft had carried out 62 flights carrying 256,000kg in military aid.
The announcement comes after Ardern on Sunday left for a tour of Spain, Belgium and the United Kingdom.
Her visit comes against a backdrop of Russia's invasion of Ukraine, which has dragged New Zealand into the orbit of the Nato security alliance.
Experts warn it risks compromising its traditional independent foreign policy, and upsetting major trading partner, China.
Ardern's first stop is Madrid where she will be a guest at the Nato leaders summit, overnight Wednesday NZ time.
New Zealand and Nato have been "partners" since 2012, and have worked in "dialogue and cooperation" since 2001, but this is the first Nato leaders summit in memory that a New Zealand prime minister has attended.
New Zealand previously gave $4.24m to Nato in March.
"New Zealand's contribution has been significant and meaningful," Ardern said.
"While in Madrid I intend to discuss the future trajectory of the war, and what additional humanitarian needs we can expect."
Other Asia-Pacific leaders from South Korea, Japan, and Australia were also invited, leading some to suggest this meeting will cement an informal expansion of Nato away from the Atlantic and into the Asia-Pacific.
The meeting is likely to focus on Ukraine and the question of a rising China, which will be included in Nato's new "Strategic Concept", a once-in-a-decade document that sets out how Nato looks at the world.
After Madrid, Ardern will travel to Brussels to attempt to advance trade talks with the European Union.
She will then head to London, where she will meet Prime Minister Boris Johnson, with whom New Zealand has just concluded trade talks and inked a widely applauded trade deal.
