Nov 15 (Reuters) - About 55,000 Canada Post workers went

on strike for the second time in six years on Friday after their

union said it had failed to reach a pay deal with the postal

operator in the run-up to the holiday season.

Federal Labour Minister Steven MacKinnon, who has twice this

year moved to end work disputes in other sectors, made clear he

was not considering another intervention for the time being.

The union is demanding wage increases in line with

inflation, cost-of-living adjustment payments to be rolled into

the basic wage rate, and safe working conditions. The union had

issued a three-day strike notice earlier this week.

"After a year of bargaining with little progress, postal

workers made the difficult decision to strike," the Canadian

Union of Postal Workers said in a statement.

Separately, Canada Post said operations would shut down

during the strike.

If the strike drags on, it could boost business for private

rivals United Parcel Service ( UPS ) and FedEx ( FDX ).

In November 2018, the Liberal government pushed through

back-to-work legislation to

end

a month-long strike by Canada Post employees.

Earlier this week, the Liberal government ordered an end to

disputes at Canada's two biggest ports and in August, it put an

end to work stoppages at the two largest railway companies.

"I'm not looking at any other solution other than

negotiation right now," MacKinnon told reporters in Montreal

when asked about the dispute.

"We are going to continue to support the parties in any

way we can and make sure that they are able to try and get a

negotiated agreement."

MacKinnon said on Thursday that he had formally

appointed a special mediator between Canada Post and the

workers' union.