Agar was Millward's assistant until last October, when he left to take charge at Featherstone, a job he subsequently gave up during the summer because his wife's ill-health.
'We know him and he knows the club, which is why he is ideal at a time like this,' the Halifax secretary, David Fleming, said. Agar, who previously coached at Bramley, Carlisle and Rochdale, will be given at least a month in the job and, although it will be advertised, he will be a candidate for the permanent position should he wish to be considered.
There is a chance that Halifax will again look to Australia for Millward's successor, although their fortunes have been mixed when they have adopted that policy in the past.
Halifax's game at home to Bradford on Boxing Day is one of several under threat from the inclement weather. St Helens will hold a pitch inspection on Saturday morning, but prospects for their traditional derby against Wigan the following day are uncertain.
If the game does go ahead, it will do so without the St Helens prop, Kevin Ward, who was sent off for tripping Castleford's Mike Ford last Saturday. Ward was last night banned for two matches.
One match that can be guaranteed to go ahead this weekend is on Headingley's heated pitch, where Leeds meet Castleford on Boxing Day morning. The Regal Trophy quarter-final between Bradford and Widnes, meanwhile, has been rearranged for Bradford City's covered pitch at Valley Parade next Tuesday.
The Leeds board issued a statement yesterday to cover their embarrassment at news leaking out of an approach to Wakefield to swap Garry Schofield, who is in dispute with the club over his aborted stint in Australia, for Trinity's two brightest young stars, Michael Jackson and Nigel Wright, plus pounds 100,000.
The board could say truthfully that they had made no approach, but the Wakefield coach, Dave Topliss, has confirmed that his Leeds counterpart, Doug Laughton, did so.
'I think it was done to frighten Garry,' he said. 'There was no question of us being interested, even if the cash adjustment was the other way.'
The cold war between the game's amateur and professional governing bodies is showing signs of thawing. The British Amateur Rugby League Association, under pressure from the International Board, has lifted its restrictions on players who turn out in the Rugby League's Academy competition.
The League has responded by removing its ban on amateurs using professional grounds. Its chief executive, Maurice Lindsay, said yesterday that 'the way is now open for immediate and earnest talks' to solve the long-running dispute over youth rugby.Reuse content