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South-east Australia was currently facing high atmospheric pressure, setting off a new national record, weather experts said on Thursday.

The weather station at Sheffield in Tasmania recorded a pressure of 1,044.6 hectopascals (hPa), at 10:30 am Thursday, which experts said, if confirmed, could break the previous record. On June 7, 1967, Launceston recorded 1,044.3hPa, ABC News reported.

The high atmospheric record is due to the intense central pressure anchored at Tasmania, which is impacting the weather from Fiji to WA west coast covering a distance of about 7,000km.

The abnormal pressure has caused extreme weather conditions over south-eastern states with clear skies, light winds and very dry surface air, resulting in low overnight temperatures and continuous rains hitting the eastern coast. Due to the additional presence of polar air, temperature had dropped to a record average of below 12 in these regions.

Temperatures across Tasmania dropped to -13C this week, leading to severe frost and icy lakes.

Melbourne recorded an overnight temperature at 1.3C on Thursday, making it the coldest in two years. Several areas in the Melbourne region dropped below 0C on Thursday morning, The Guardian reported.

The high pressure is expected to peak again on Saturday, before weakening on Sunday.

"The strong high pressure system was influenced by a split jet stream over Western Australia and large upper lows over South Australia and the Tasman Sea "enhancing the subsidence into the high," Yoska Hernández, a Weatherzone meteorologist said.

As the pressure intensified, several regions were affected by low winds cutting off electricity, leading to burning of more gas to generate power.

Based on Australian Energy Market Operator, between June 17-23, the storage levels at Victoria's main Iona site dropped by 2.6 petajoules, which was a record. Over a fortnight, Iona's storage lost 4.1PJ, dropping from 78% full to 60%.

The gas output from the Longford facility tapping Bass Strait gas had increased to meet the rising demand. It was an indication that supply may be tight till the end of winter.

Some relief may arrive in the form of a cold front expected to cross Victoria next week. More wind generation could ease the pressure on gas-fired power stations, Hernández said.