The Singapore Grand Prix looks unlikely to take place on the revised 2020 Formula 1 calendar, although race promoters remain in “open dialogue” with championship officials.

F1 is currently working on a rescheduled 2020 calendar in its bid to get the delayed season underway amid the ongoing COVID-19 pandemic.

Championship bosses hope to stage a series of back-to-back closed door races in Europe to kick off the campaign, with Austria identified as the season opener on July 5 before consecutive events at Silverstone on July 26 and August 2, although plans to return to the UK may yet be scuppered by the government’s coronavirus-related travel restrictions.

So far the Australian, Monaco and French grands prix are the only events to be fully cancelled, although it has emerged that the Dutch, Canadian and Singapore rounds are also missing from the latest version of the 2020 F1 schedule.

Although there has been no official confirmation regarding the event, Singapore - which was originally given a September 20 date - is less flexible to move dates given it is a city-based street track and typically requires around three months lead time to set up the temporary race infrastructure.

Unlike other venues, Singapore GP race promoters insisted it is "not feasible to conduct the race behind closed doors”.

An event spokesperson said: "The calendar for the 2020 season is currently being finalised and Singapore GP has been maintaining an open dialogue with F1, the Singapore Government and our stakeholders during this time, to assess different possibilities.

"The top priority remains the well-being and safety of our fans, volunteers, and all Singaporeans.”

Hopes of staging a race in Singapore could also be curtailed by international travel and quarantine restrictions, while the county’s own measures for September are unclear at this stage.

It recently extended its lockdown measures until early June following a fast-growing second surge of infections towards the end of April.

On Friday, Singapore’s National Development Minister Lawrence Wong stressed it is still too early to say when curbs will be relaxed amid discussions about lifting travel restrictions between Singapore and other countries.

The Singapore Government did give building contractors the green light to resume work from June 2, although all projects will need the Building and Construction Authority’s approval before they can restart.

Question marks also remain over financial agreements and whether the Singapore race’s hosting fee - estimated to be around $30million - would be waived by F1.