All Blacks captain Kieran Read and British and Irish Lions captain Sam Warburton pictured after the drawn series last year.

The Rugby Football Union (RFU) and Celtic Unions are at loggerheads over a plan to ensure the British and Irish Lions have more time to prepare for tours.

Nigel Melville, the RFU interim chief executive, has attempted to instigate talks between Premiership clubs and the Lions regarding player release and training time.

But the clubs have resisted demands to cut their season by one week in seasons (every four years) when the Lions are touring, meaning Melville will revisit an old proposal.

The Lions are keen to avoid a repeat of last year's tour of New Zealand, when the Warren Gatland-coached Lions arrived in the country just four days before their first fixture - against the Provincial Barbarians in Whangarei.

Previous attempts to reduce the Six Nations from seven to six weeks, by flagging one of two rest weekends, have been rejected.

The RFU are set to revisit the the plan ahead of the Lions' tour of South Africa in 2021, which will consist of eight matches, two fewer than recent tours.

PHOTOSPORT Mako Vunipola and the Lions had just four days to prepare to play the Provincial Barbarians in Whangarei last year.

"They need an extra week," Melville told the Daily Mail. "If every four years we move the Six Nations from seven to six weeks, you create that. So why don't we do that?

"It would be better preparation for the Lions. Instead of coming out of a final and going straight into a Lions tour, how about you have the extra week? That would make a difference."

The overbearing influence of English clubs didn't sit well with many after last year's Lions' tour, after they refused to alter their schedules.

Melville wants that to change, but isn't holding his breath.

"It's a balance. We've got to get movement in that fourth year. That [Six Nations plan] is an opportunity to get movement, if the Premiership weren't prepared to move. It would require the support of Ireland, Scotland and Wales — France and Italy as well, who have no stake in the Lions," he told the Daily Mail.

"I was a Lion. The old-fashioned tour has gone. But you have a three-test series and you want the best preparation. Is it worth fighting for? Of course it is.

"I'm on the Six Nations board, so I can certainly discuss it. We have to look at things slightly differently sometimes to protect what we think's important — and the Lions is incredibly important."