Grant and Alana Williams have dissolved their powerhouse training partnership as new vaccination mandates take effect in Western Australia this week.

Already this season, the stable have amassed 44 wins from their 167 starters, including a clean sweep of all three Group 1 races in Perth: the Railway Stakes, Winterbottom Stakes and Kingston Town Classic.

The husband and wife duo have been predominantly associated with owner Bob Peters and star hoop William Pike, who makes his move to New South Wales this week.

Earlier in the year, Racing and Wagering Western Australia announced that all racing participants in the state would need to be double vaccinated against COVID-19 by Monday, January 31, should they wish to attend a race meeting.

While the reason for the split has not been revealed, it is suspected that Alana Williams has not been vaccinated, which is why her name came off the partnership on Monday morning.

Grant Williams will continue training, with all of the couple's horses now registered under his name.

Williams will have his first runners as a standalone trainer at Belmont on Wednesday as Prince Ragnar, Crossaro and Trevello step out, before Red Fifty Three attempts to make it four wins from as many starts in Saturday's $200,000 Magic Millions WA 3YO Trophy (1200m) at Pinjarra Park.

The son of Gingerbread Man has been impressive in all three wins to date, leading all of the way in his past two starts in September.

The gelding recently trialled at Lark Hill, where he was given an easy time under Paul Harvey, finishing within a length of the winner.

Harvey will retain the ride on the unbeaten galloper, with the pair set to jump from barrier 11 in the 3YO feature.