Tony Abbott says the presence of Russian warships off Queensland before tomorrow's G20 meeting is another sign of Moscow's growing military assertiveness.
_The West Australian _ believes the Defence Department is continuing to track four Russian vessels heading south through international waters in the Coral Sea.
Australia has rushed two frigates - HMAS Parramatta and HMAS Stuart - to intercept and shadow the Russian ships.
A tag team of RAAF P-3 Orion surveillance aircraft have been observing the Russian ships.
The Russian naval task group includes the heavily armed destroyer Marshal Shaposhnikov and guided missile cruiser Varyag.
There is speculation the vessels will be parallel to Rockhampton by the weekend, though they will almost certainly remain far out in international waters.
The Prime Minister played down suggestions the Russian warships were sent as a direct threat to Australia amid tensions over the MH17 disaster but said Moscow was increasingly keen to flex its military muscles.
"It's not unusual for Russians to deploy in the vicinity of major conferences and let's not forget that Russia has been much more militarily assertive in recent times," Mr Abbott said.
"We're seeing, regrettably, a great deal of Russian assertiveness right now in Ukraine."
He rejected any idea the Russian ships were deployed in response to his warning he would "shirt front" President Vladimir Putin to express his anger over MH17.
Mr Abbott said the ships must have set sail many weeks ago, long before the shirt-front comment.
Russian Defence Minister Sergei Shoigu said yesterday Russia would begin regular air patrols from the Arctic Ocean to the Caribbean and Gulf of Mexico.
The announcement was made as NATO said it had seen columns of Russian military equipment and combat troops entering Ukraine.
In recent months, European nations have been forced to scramble fighter jets to intercept probing flights of Russian bombers.
NATO says alliance nations carried out more than 100 intercepts of Russian aircraft this year - three times more than last year.
Government sources said the Russian naval task group likely included a submarine but it had not been spotted.
US nuclear-powered attack submarine USS Hawaii is currently in Perth.