Scott Morrison has said he expects MPs to “be in their electorate”, offering a mild rebuke to George Christensen after a report the Nationals MP spent more time in the Philippines than in parliament in 2016 and 2017.

Morrison said on Wednesday Christensen had “not spent a day in the Philippines” while he was prime minister and declined to criticise him more directly for what he said was “private business”.

The Herald Sun reported the influential conservative backbench MP made 28 trips to the Philippines between April 2014 and June 2018, spending a total of 42 weeks there, including 72 days in 2016 and again in 2017, more days than the House of Representatives sat in those years.

In December Christensen identified himself as the government MP who came under federal police scrutiny for frequent travel to south-east Asia, but dismissed the reports as part of a “disgusting smear campaign”.

Christensen reiterated that defence in response to the latest story, reportedly telling the Herald Sun it was a “smear campaign” from Labor and a “former very senior Liberal MP”, and he had never used taxpayers’ funds for private travel.

“As far as I’m concerned and the facts are concerned, this matter is over.”

Morrison told reporters in Sydney that Christensen “hasn’t spent … a day in the Philippines since I’ve been prime minister – not a day”.

“I endeavoured to contact him actually yesterday but we were both travelling at the time – in Australia I should stress – and I’ve spoken to the leader of the National party about it and he’s making comments about this as well.

“But I can tell you: it hasn’t happened on my watch … I expect members to be in their electorates doing their job.”

Morrison refused to comment about whether the AFP had provided a briefing about a government MP’s travel to south-east Asia, explaining it would “be a very reckless thing for a prime minister to do in any situation”.

“It’s [Christensen’s] private business. I don’t go into his private business. He wasn’t travelling there officially, as my understanding was, and so what he does in his private time is a matter for him.”

Labor senator Murray Watt accused Christensen of being “missing in action”.

“Rather than fighting to protect north Queenslanders, Christensen has been thousands of kilometres away, for over two months a year,” Watt said in a statement.

“How can Christensen justify such regular and extended absences from work?

“If Christensen doesn’t want the job, he should leave it to someone who does.”

The resources minister, Matt Canavan, has defended Christensen, describing him as a dedicated local MP.

“This is a massive beat-up which is an invasion of George’s privacy as well,” Canavan told Sky News. “His fiancee is from the Philippines. I think it’s great he’s met someone to spend his life with, and good luck to him.

“He’s done a lot of charity work in the Philippines as well through his church. He’s spent his money doing this as well.”