Scott Morrison and the premiers will discuss the timetable for easing Covid-19 restrictions, including the opening of borders, and look at physical distancing rules for indoor gatherings and for flights when national cabinet meets on Friday. The meeting is also expected to canvas an acceleration of infrastructure projects to provide economic stimulus and job creation, as well as options for state and federal cooperation on deregulation. Friday’s meeting of leaders comes as the Australian Health Protection Principal Committee has urged Australians not to participate in mass gatherings, describing protests as a “very high risk environment” given thousands of people are in close proximity, and there are difficulties in subsequently identifying all contacts. A person who attended the mass Black Lives Matter protest in Melbourne last weekend has tested positive to Covid-19, and Scott Morrison on Thursday intensified criticism of the activism, declaring people ignoring the public health advice should be charged by authorities. Morrison in parliament on Thursday acknowledged that Indigenous deaths in custody was a matter of “national shame” but he argued the recent Black Lives Matter protests put “the whole track back to economic recovery at risk” and could delay easing of restrictions by a week while governments monitor signs of outbreaks. In a radio interview ahead of Friday’s national cabinet meeting, the prime minister said the weekend protests had interfered with the capacity of states to ease physical distancing rules, including allowing more people to attend funerals. Chief medical officers said late on Thursday it would take “some days” to determine whether other people had been infected at the protests. The AHPCC statement said Victoria has launched “a significant investigation to determine the source of the infection and identify close contacts”. Victoria’s chief health officer, Brett Sutton, has said it was unlikely the infection had been acquired at the protest, but it was possible the person was infectious. The man, in his 30s, wore a mask. Australia’s chief medical officer, Brendan Murphy, said if the coming weeks showed only a small spike in Covid-19 infections among protest attendees, “then obviously it’s easy to cope with and we can contact trace, contain, isolate, quarantine as we’ve done, you know, really for the last few months”. “But I think the biggest worry is that we have a large number of outbreaks that seed more community transmission,” he told the ABC’s 7.30 program on Thursday evening. “We’ve got almost no community transmission in Australia at the moment. It’s a fantastic position … so that’s what we want to keep.” On the easing of restrictions, Murphy said every state and territory was in a different place and health officials wanted to make sure “that we relax our restrictions carefully and progressively” and monitor the impact. Murphy said the lack of an upswing in cases after the recent relaxation in rules was “a really good sign” that would give governments confidence to progressively loosen controls, “but if you go too far too quickly you can get a larger outbreak”. In the interview, Murphy acknowledged there was a risk of the public losing interest in complying with the rules given the low number of Covid-19 cases at present. He agreed that there was “some arbitrariness” about some of the regulations, but added there was “no rule book to this” and officials were “doing what they can with the best of information that we have”. While issuing warnings against mass gatherings, Morrison has attempted this week to step up pressure on the premiers to open state borders to assist with normalising economic activity. But the premiers have signalled they will move at their own pace. The Western Australian premier Mark McGowan said late on Thursday he would reopen the border when it is safe to do so. “We have opened up our economy within WA to a far greater degree by a country mile than any other state in Australia. That’s got far more people back to work”. The Queensland premier Annastacia Palaszczuk said the state was tracking towards a border opening in July. “July will definitely see more of Queensland opening up,” the premier said. “We will see more people in restaurants and cafes, we will see more people in activities, more people in stadiums, so July is going to be a very good month for Queensland.”