The ice is 501,930 sq miles (1.3 million sq km) below the previous low record for this time of year – an amount that is more than five times the surface area of the UK.
Dr Ed Blockley, who leads the Met Office's Polar Climate Group, said: "Antarctic sea ice extent reaches a maximum around the end of September and a minimum around the end of February.
"At the end of June, the extent of sea ice should be building to a mid-point between the maximum and the minimum.
"However, this year the ice is expanding very slowly with the consequence that the extent is way below the long-term (1981-2010) average.
"The annual minimum extent in February 2023 was the lowest since satellite records began in 1979, just over one million sq km (386,102 sq miles) below the long-term average.
"The current extent is extraordinarily low: it is in excess of 2.5 million sq km (965,255 sq miles) below average for the time of year."
Scientists believe that El Nino, a cyclical phenomenon which warms the tropical eastern Pacific Ocean and affects air temperatures worldwide, coupled with anomalous atmospheric circulation patterns around Antarctica, could be preventing the sea ice from recovering as much as it usually does in winter.
Temperatures on the southern continent will continue to fall as winter advances, which will give the ice more time to extend further.
Dr Blockley said: "It is too early to speculate whether ice extent will remain at extremely low levels. There is still time this season for the ice to recover, but given the record lows we have seen we have to remain concerned about the likelihood of a record low winter maximum."
