Australia’s prime minister, Scott Morrison, has weighed into the Ashes booing debate, calling it “a foul” for English fans to jeer Steve Smith after he suffered a concussion during the second Test at Lord’s.

The batsman had to leave the field on Saturday after he was struck on the neck by a 92.4 mph delivery from the England fast bowler Jofra Archer, which knocked him to the ground and has reignited debate about head safety in cricket.

Smith returned to the crease 40 minutes later, before being dismissed for 92. While many fans offered him a standing ovation, an audible contingent booed and jeered, both when he was withdrawn and when he returned.

The brain injury charity Headway has since said Smith should not have returned, and the batsman was replaced on Sunday under new concussion substitution guidelines after he woke up feeling dizzy and failed cognition tests.

On Monday Morrison added his voice to the growing number of Australians condemning the continued jeering of Smith. The former Australian captain has been booed by English fans throughout the World Cup and the start of the Ashes, along with the openers David Warner and Cameron Bancroft, for the trio’s role in last year’s ball-tampering scandal in South Africa, for which all three were suspended.

“It was a total Ashes foul for the crowd at Lord’s to boo Steve Smith,” Morrison said in a Facebook post. “His performance on the pitch during his return to test match cricket in the UK demands nothing other than respect.”

The prime minister said Smith had handled his year-long suspension for his role in the ball-tampering scandal “with a real humility”.

“The crowd could learn a thing or two from Steve Smith and I look forward to him answering his hecklers with bat and ball in hand to bring home the Ashes.”

The England supporters group the Barmy Army issued a statement saying they were not involved in the boos at Lord’s.

The former Australian wicketkeeper Ian Healy said the jeering was “disgusting”, adding: “Lord’s won’t be happy with that either. They don’t like any ‘yobbo’ element of crowd behaviour.”

The former Australian captain Mark Taylor echoed the sentiment, describing the booing as “very disappointing”.

In 2014 the Australian batsman Phillip Hughes died after a similar blow to the neck, prompting the introduction of StemGuards – additional neck protection that clips on to the helmet.

On Sunday, Smith told reporters he did not wear the guard because he found it “uncomfortable” and “claustrophobic”, but would now reconsider.

“It is certainly something I need to have a look at and perhaps try in the nets and see if I can find a way to get comfortable with it,” he said.

Australia’s coach, Justin Lange,r echoed his concerns, saying Smith “might rethink it now after seeing what happened today”.