staff called in sick with mystery illnesses.

And officials admitted yesterday they were not even sure if the workers had staged an unofficial strike.

Customs officials frantically drafted in extra staff from Hamilton and St.

George's when the employees rang in sick yesterday morning.

But Collector of Customs William LeDrew said not one of the 13 had told him of any industrial action.

Union representatives from the Bermuda Public Services Association were also puzzled, he added.

Now senior Customs officers will head up an inquiry and quiz the workers when they return to work on Thursday.

Mr. LeDrew said last night: "Whether this is an industrial action or not, we just don't know.

"We haven't spoken with any of the officers yet and at this stage, it's nothing more than a number of officers who have called in sick and they are entitled to do that under their contract.

"I have spoken to the Customs Council, the Customs arm of the BPSA, and they advised me they were unaware of any organised action.'' But he added: "I am not naive. Over any given time we have people out on sick leave.

"However, this is too great a coincidence in my view. We will talk to the staff when they are back on Thursday -- because they work every other day.

"But the first priority is to make sure we have got enough people here to provide a service to the public. The second thing is to get to the root of the problem and find out if there is an issue.'' The Airport normally has around 28 Customs workers on duty. But the 13 "ill'' staff, plus three on long-term sick, depleted yesterday's shift -- so extra officers were drafted in as an emergency measure.

And the four lunchtime flights arriving from the US were not disrupted, according to Mr. LeDrew and Airport general manager Jack Gordon.

"We have managed to coped and we deployed some additional staff,'' added Mr.

LeDrew. "I don't think travellers noticed any difference.'' The Customs chief said some officers had voiced concerns about staff shortages and conditions of work at the Airport, where the baggage hall is still being extensively refitted.

Airport Customs officers hit by `mystery illness' But he said he had already written to staff, praising them for working well under "very difficult circumstances''.

Mr. LeDrew said conditions were now "much better than they were'', adding that the work would be finished within weeks.

He also said Bermuda's Customs workforce now stood at just two below its full complement of 144 staff.

BPSA General Secretary Edward Ball said his own officers were already trying to contact Customs workers to find out why they called in sick.

"I don't even know what's going on myself yet,' he said. "I have been able to ascertain that this may have something to do with staffing problems on a particular shift but I cannot confirm that until we get hold of the workers.''