The big swing to cropping has seen the number of sheep sent to slaughter in January, February and March increase by 30pc compared to the same period last year.

In total 892,000 sheep were sent to slaughter for the March quarter.

That is the highest number since 2000 and, previous to that, compares to numbers in 1993.

The worrying thing is that the amount of mutton being slaughtered is on the rise.

Processors are now concerned that while they are running at full capacity at the moment, where will the sheep come from in 12 to 15 months time?

Meat and Livestock Australia chief market analyst Peter Weeks said the organisation was not reviewing its national sheep flock projections just yet, but did admit that WA would continue to face reductions in sheep numbers going forward.

"Nationally lamb slaughterings are running above our expectations, certainly for the March quarter," Mr Weeks said.

"But there are more Merinos going to slaughter in WA.

"Mixed farmers who have already committed to increases in cropping must be very tempted to offload additional lambs and sheep going into winter.

"There was also an increase in WA lamb kills in November and December last year as high grain prices saw farmers not planning to grain feed and quitting stock earlier than usual.

"WA lamb slaughterings since July last year to March this year have increased to 1.84m, up from 1.8m the previous year. Over the same period nationally they are up by 6pc.

"In March alone though there were 27pc less lambs slaughtered than the same time last year and this reflects the fact that most of the lambs have gone out of the system already."

WAMMCO chief executive officer Des Griffiths said the number of sheep coming into the works was sounding warning bells for the future.

"We expected a major fall off by the end of March, but the works is still at full capacity," Mr Griffiths said.

"While it is good for now that we can work to full capacity, the declining sheep flock could have done with rebuilding rather than a sell off."