* Australia reports 151 new cases, up from 121 day earlier
* Officials concerned about a drop-off in testing rates
* New Zealand reports 7 new cases, launches testing blitz (Recasts and updates throughout with new daily tally, NZ figures and quotes)
By Colin Packham
SYDNEY, Aug 25 (Reuters) - Australia surpassed 25,000 COVID-19 cases on Tuesday, tipped over the milestone by the recent outbreak in Victoria state and prompting a warning from authorities about declining test numbers.
Australia recorded 151 new infections over the past 24 hours, up from 121 a day earlier, with Victoria responsible for the bulk of the cases and New South Wales accounting for the remainder.
The daily numbers were well down from a peak during Australia's second wave of more than 700 in a single day earlier this month, but officials expressed concern about a drop-off in the number of people presenting themselves for COVID-19 tests.
"We are seeing some decrease in the amount of testing ... please, if you have symptoms, do go and get tested," national Chief Nursing and Midwifery Officer Alison McMillan said during a televised media conference in Canberra.
The new cases took Australia's tally since the pandemic began to 25,067 cases, including 525 deaths.
Melbourne, the capital of Victoria and the country's second largest city, is the epicentre of the renewed outbreak. The city is just over halfway through a six-week strict lockdown, which requires residents to remain at home unless on essential business. Businesses have been forced to close and a nightly curfew imposed.
Premier Daniel Andrews is attempting to push legislation through state parliament to extend Victoria's state of emergency declaration by another year, giving him the ability to extend or reimpose restrictions over that period.
NEW ZEALAND TESTING BLITZ
In neighbouring New Zealand, officials announced a testing blitz as they reported seven new COVID-19 cases over the past 24 hours. Health Minister Chris Hopkins said 70,000 tests were planned over the next week.
"We haven't quite got this cluster completely identified yet, we do need people to take that test when asked," Hopkins said in Wellington, referring to a group of cases in the city of Auckland that earlier this month ended the country's months-long run with no locally transmitted cases.
Prime Minister Jacinda Ardern on Monday extended a lockdown in Auckland until the end of the week and introduced mandatory mask wearing on public transport across the nation.