* Mining stocks hit their lowest in a week

* Australia's "Big Four" banks down more than 1%

* NZ to lift restrictions across country, except in Auckland

Sept 21 (Reuters) - Australia shares on Monday ended at their lowest since the end of June, dragged lower by the so-called "Big Four" banks and major miners, which fell more than 1% on weaker iron ore prices.

The benchmark indexes in both Australia and New Zealand ended in the red for a third straight day, with Sydney's ASX 200 down 0.7% and Wellington's NZX 50 closing 0.8% lower.

Top iron ore miners Rio Tinto, BHP Group and Fortescue Metals Group fell 1.2% each as prices of the steelmaking ingredient dropped 2.2% on Monday due to sluggish downstream demand and fresh environmental restrictions in a main steelmaking area.

Property manager Dexus was among the top losers on the Australian benchmark after Morgan Stanley slashed its rating to "underweight" and raised doubts over when the work-from-home era will end.

Banks also came under pressure with Australia's "Big Four" lenders down between 1.3% and 1.5%.

The drop comes amid heavy global losses among top lenders such as HSBC and Standard Chartered after media reports said the banks and others moved large sums of allegedly illicit funds over nearly two decades despite red flags about the origins of the money.

"News about what's happened in illicit transfers through the banking system in the United States is hitting the banks in Europe as well as in Asia, so we expect that's going to hit the U.S. market as well", said Mathan Somasundaram, a market portfolio strategist at Blue Ocean Equities.

The New Zealand benchmark index closed at its lowest in more than a month with corporate travel management firm Serko leading losses with a 4.6% drop.

Meanwhile, Prime Minister Jacinda Ardern said all coronavirus restrictions across the country were lifted, except in the second-wave hotspot city of Auckland. (Reporting by Deepali Saxena in Bengaluru, Editing by Sherry Jacob-Phillips)