Cash-strapped licensees who cut down staff hours could find themselves hauled before employment tribunals unless they follow the right procedures.
Lawyer Stephen Mutch revealed an increasing number of hosts are running into trouble after telling staff their working hours are being cut.
Mutch said licensees ran the risk of being sued for unfair dismissal if workers decided to resign in protest at their treatment.
"This is becoming an issue as licensees look to cut costs by reducing their wage bill," Mutch told delegates at the Federation of Licensed Victaullers Associations' (FLVA) annual meeting.
"If you cut hours without the consent of staff it gives them an opportunity to re-sign and claim against you for unfair dismissal," he said.
Mutch, of solicitors Pannones, said licensees needed to get the consent of staff before altering their hours.
"There are ways out for licensees, particularly if staff object to the reduction, but work the new hours, which means they lose their right to contest the decision.
"But employers do need sound business reasons to reduce hours and there must always be a process of consultation.
"I would urge anyone considering cutting back staff hours to take advice first," Mutch said.
Also at the meeting, an MP pledged to redouble his efforts to force supermarkets to abandon below-cost selling of alcohol.
Federation Parliamentary advisor Eric Illsley claimed the supermarkets were putting two fingers up at the Government's attempts to bring them into line.
Illsley, MP for Barnsley Central, said selling whisky for £5 a bottle was "clearly wrong".
He told delegates: "There is nothing wrong with the odd special offer, but when it happens day in, day out, it has to be stopped, especially when the pub trade is dying on its feet.
"You cannot stop promotions, but you can stop irresponsible promotions.
"The Government has to realise what is happening. The pub is an institution and has to be protected," he added.
Barnsley licensee Dennis Griffiths was named as the new FLVA president at the event. Griffiths runs the town's Miners Rest pub.