US Secretary of State Rex Tillerson arrived in Beijing today to discuss efforts to curb North Korea's nuclear ambitions and prepare President Donald Trump's upcoming visit to China.

Tillerson was scheduled to meet with President Xi Jinping after talks with top diplomat Yang Jiechi and Foreign Minister Wang Yi, ahead of Trump's trip in November.

The visit comes as relations between the two superpowers appear to be improving after months of tensions over how to handle North Korean leader Kim Jong-Un's nuclear provocations.

Trump has repeatedly urged Xi to exert more economic pressure on Pyongyang to convince the renegade regime to give up its nuclear ambitions.

China, North Korea's main trade partner, has responded by backing a slew of new United Nations sanctions.

For its part, Beijing has insisted that the sanctions must be coupled with efforts to organise peace talks, but Trump and Kim have traded increasingly personal insults that have raised fears that the crisis could spark a conflict.

The acting US assistant secretary for East Asia, Susan Thornton, told sceptical US lawmakers ahead of Tillerson's trip that China appears to be on board with the plan to squeeze Pyongyang.

"We are working closely with China to execute this strategy and are clear-eyed in viewing the progress -- growing, if uneven -- that China has made on this front," she said.

"We have recently seen Chinese authorities take additional actions," she said, referring to new controls on the cross-border trade and finance that is North Korea's economic lifeline.

On Thursday, China said it was ordering North Korean firms on its territory to close by January.

The announcement came days after China confirmed it will limit exports of refined petroleum products to North Korea from October 1 while banning imports of textiles from its neighbour.

The measures were in accordance with UN sanctions that were approved earlier in September after North Korea detonated its sixth and most powerful nuclear bomb -- a test that triggered an earthquake felt across the border in China.

Trump's November trip will be part of a tour that will also take in regional allies Japan and South Korea.