In a joint letter with the chair of London Councils, Khan told Housing Secretary Robert Jenrick an extension will provide a 'lifeline' to businesses in the capital that have been hit particularly hard following the collapse in tourism.
As things stand, rates are due to be reintroduced at the beginning of the new financial year in April 2021.
At the onset of the Coronavirus pandemic in March, Chancellor Rishi Sunak announced all retail and hospitality firms were exempt from paying business rates for 12 months to help businesses as they struggled with the financial damage caused by the outbreak.
Khan previously demanded an extension to the business rates holiday back in September, as fears over the scale of job losses caused by the pandemic mounted.
In his latest letter, the Mayor also asked for support via the Local Restrictions Support Grant and Discretionary Grants, which support businesses that have had to close due to temporary Covid-19 local lockdown measures or have suffered a fall in income as a result of the coronavirus crisis.
He asked for these grants to be tailored appropriately, in order to account for the rental and rateable values in London.
It comes as hospitality venues in London and across England prepare to close their doors for at least a month from Thursday (5 November), as the Government plunges the country back into lockdown.
Under the restrictions, all restaurants, pubs and bars in England must close, although takeaways and deliveries will be permitted.
Responding to the Prime Minister's announcement regarding the lockdown, Gaucho and M CEO Martin Williams called for the Government to extend all rates and VAT relief and rent protections for the sector, to ensure hospitality businesses big and small have the opportunity to come out the other side.
"Given that the Government have again enforced this lockdown, it is essential that the rent moratorium to protect tenants is extended until April [2021]," he said.
"I go further and suggest that the rent moratorium, rates and VAT relief are all extended until June 2021, this will give genuinely good businesses in hospitality the opportunity to come out the other side of this.
"Whilst I believe many of the British public will question the rationale behind this decision [to lockdown] versus the opportunity to retain liberty, protect the vulnerable and to self-regulate, whilst getting the economy re-started, the lockdown is here and something we have to live with.
"However, it is essential that we reopen in December, without curfew and most importantly, without the one household restriction.
"The Tier 2 and 3 rulings make almost all hospitality businesses non-viable and we need to return to the ‘rule of six’ as the worst case scenario.”
In terms of recovery, Williams went on to mention Khan directly.
“I believe the Mayor of London now needs to step back and decide if he is pro-business as he has claimed," he said.
"If he takes the next month to plan the reopening of the tube network - most importantly the Waterloo and City line - and focus his energy on encouraging the companies in The City to safely return to work and get the whole economy moving again, we have a chance of kickstarting 2021.”