WELLINGTON (AFP) - The International Cricket Council unveiled a long-awaited, nine-nation Test championship on Friday in a bid to preserve the five-day format's status following the rapid growth of Twenty20.

The Test league was among a raft of reforms agreed at an ICC board meeting in Auckland, including revamping the one-day international schedule and trialling four-day Tests.

"Our priority was to develop (a) structure that gave context and meaning across international cricket and particularly in the Test arena," ICC chief David Richardson said in a statement.

The Test league will start in 2019 and see nine teams play six series over two years - three home and three away.

It will culminate in a final between the two top teams at Lord's.

The ICC has argued for years that a Test championship is needed to boost the format's popularity as crowds and TV viewers flock to the fast-paced, big-hitting Twenty20 version of the game.

It first appointed a committee to examine the concept back in 1998. But squabbling over formats, and fears that some nations will be disadvantaged, have twice stymied efforts to launch a league structure since 2010.

"Bringing context to bilateral cricket is not a new challenge, but this is the first time a genuine solution has been agreed on," ICC chairman Shashank Manohar said.

The nine nations in the competition are Australia, Bangladesh, England, India, New Zealand, Pakistan, South Africa, Sri Lanka, and West Indies.

Cricket Australia chief James Sutherland called it "a really significant moment in international cricket history".

"It's a tremendous step forward," he said. " The ICC and member countries have made a strong statement about international cricket and how we want to make sure it remains at the forefront of the three forms of the game."