It is their first encounter since an acrimonious phone call in February.
"We get along great. We have a fantastic relationship, I love Australia, I always have," the AFP news agency quoted Mr Trump as saying.
Protesters also gathered in Mr Trump's home city, the first time he has returned there since his inauguration.
Mr Trump said the two leaders had "reaffirmed ties" between their two countries, and discussed economic, trade, and national security co-operation, as well as migration issues.