The Mayor of London "expects an invite" to Boris Johnson's emergency meeting to discuss restrictions to halt the spread of coronavirus.
Sadiq Khan met with London council leaders on Monday after data showed the capital was "catching up" with Covid-19 hotspots in northern England.
Public Health England figures show there have been over 2,000 new positive cases in London in the last week.
Mr Khan said the last time he spoke with Boris Johnson was on 10 May.
It comes after the UK upgraded its covid alert level, amid a rising number of cases, the country's chief medical officers have said.
Chief Scientific Adviser Sir Patrick Vallance warned the UK could see 50,000 new coronavirus cases a day by mid-October without further restrictions.
Mr Khan said that "without adequate testing or contact tracing in London" he would have no choice but to look at bringing back some restrictions to slow the spread.
"I firmly believe that acting early, rather than having to impose more stringent measures later, is the right thing to do both for public health and the economy," he said.
"Given the huge impact these will have on London, I expect to be invited to the Government's COBR meeting to discuss his plans tomorrow morning."
Measures in place in north-east and north-west England include a ban on meeting with other households or support bubbles in private homes and gardens, not socialising with those outside your household in public venues, and using public transport only for essential purposes.
Pubs, restaurants and cafes are table service only and all leisure venues must shut at 22:00 BST. Care homes are closed to non-essential visitors except in end-of-life circumstances.