The trunk and arms mixed double scull combination won their repechage at the world titles in Slovenia on Tuesday night (AEST) to progress to the A final.

It means they are guaranteed a top-six finish at the regatta, qualifying Australia for next year's Paralympic Games in London.

Ross and Maclean, who will still have to be selected in the crew next year despite their success, became the first Australian crew to qualify for the London Olympic or Paralympic Games.

"The qualification is definitely a weight off our shoulders," Ross said.

"To have qualified the boat for Australia is great and now we can focus on the final."

The 2008 Beijing Paralympic Games silver medallists advanced to the final after winning their repechage in Bled in a time of four minutes and 10.82 seconds, which was 1.1 seconds ahead of rivals Great Britain.

The duo will chase a medal in the final on Saturday.

"It's great that we have the first box ticked," said Ross, who trains at the Australian Institute of Sport.

"Hopefully we can win a medal in the final but it will be very tight racing and very close."

Penrith rower Maclean said that he and Ross improved on their heat from earlier this week, which saw them edged out by Ukraine.

"It's fantastic to qualify the boat for the final and ultimately qualify it for the Games next year," Maclean said.

"Kat did a great job today and we can look forward to the A Final now.

"We turned it around pretty quickly from (the heat).

"We sat down as a crew and talked about what we needed to do and then went out and got the result."

kbutler@standard.fairf ax.com.au