The United States has developed "advanced" methods of communicating with North Korea on its nuclear and missile programs, according to Australia's Foreign Minister.

Key points: Julie Bishop says Australia won't be sending a delegation to the rogue state

Julie Bishop says Australia won't be sending a delegation to the rogue state Donald Trump has previously said it's not worth wasting time negotiating with North Korea

Donald Trump has previously said it's not worth wasting time negotiating with North Korea Ms Bishop is concerned North Korea may use next week's Communist Party Congress as an excuse to launch another missile

Secretary of State Rex Tillerson has revealed the US is in direct communication with Pyongyang, but President Donald Trump has told him not to waste his time trying to negotiate with leader Kim Jong-un.

"I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man," Mr Trump wrote on Twitter, using his sarcastic nickname for Mr Kim.

The President's comments came after Mr Tillerson told a small group of reporters last weekend that the US was probing North Korea to see whether it was interested in dialogue.

"We are probing, so stay tuned," he said.

Mr Tillerson said the United States had "a couple of, three channels open to Pyongyang".

A senior US official, asked for clarification about Mr Trump's tweets, played down the significance of the communication channels.

But Foreign Minister Julie Bishop has now effectively ruled out sending an Australian delegation to the rogue state, confirming the US is having some success communicating with it.

"I believe that the United States is rather advanced in its back channelling with North Korea," Ms Bishop said.

Ms Bishop has dismissed suggestions Australia's embassy in Pyongyang, which has been closed since 1974, could be reopened.

"We work with other countries who do have a presence in Pyongyang, but I believe they have limited success in engaging with the regime," she said.

Bishop warns of possible missile test next week

Ms Bishop and Defence Minister Marise Payne are visiting South Korean counterparts this week, to address the North's pursuit of its nuclear and missile programs.

The Foreign Minister said there were real concerns North Korea may use a meeting of senior Chinese officials next week for another missile test.

The 19th Communist Party Congress will be held in Beijing next Wednesday and delegates will decide government policy and elect officials to run the country for the next five years.

"North Korea may use that opportunity to further embarrass China by having another nuclear test or letting off another ballistic missile," Ms Bishop told Sky News.

"There seems to be some pattern to North Korea's behaviour in having these illegal tests at the same time China is showcasing their nation on the world stage."