Australia will halve the number of international arrivals this month to alleviate the pressure on the country's hotel quarantine system from the highly transmissible Delta variant of the coronavirus, Prime Minister Scott Morrison said Friday.

The further restrictions on passenger arrivals from overseas come as Australia battles with simultaneous outbreaks of the variant in Sydney and two other major cities, placing nearly half of the country's population under strict lockdowns.

Under the measure set to come into force by July 14 and remain until Aug. 31, weekly caps on international arrivals will be reduced from around 6,000 to about 3,000.

Morrison indicated that the reduced caps will likely continue until at least the beginning of next year, though the caps will be reviewed regularly for the rest of 2021.

Australia has successfully relied on strict border controls to keep the nation's infections levels low over the course of the pandemic, largely restricting non-citizens from entering the country since early last year.