Dozens of liquefied natural gas (LNG) tankers parked in and around Qatari export facilities - the world's biggest hub for the fuel - signal that seasonal maintenance is curbing output, industry sources said.

Around 25 tankers, all of which have exported LNG from Qatar in recent weeks, are sitting idle in anchorage areas near to the country's loading ports, shipping data on Reuters Eikon shows.

Several industry sources said that maintenance on one of the production plants, or trains, at top exporter Qatargas was likely to blame for the logjam of idle vessels.

Qatargas did not return requests for comment.

"This is the usual maintenance period (for Qatar) which they operate on a rolling basis," one LNG trader said.

According to Thomson Reuters analysts, Qatar is set to export 23 percent less LNG this week than it did last week.

Qatar's two LNG exporting ventures, Qatargas and RasGas, operate a rolling schedule of maintenance on production trains to carry out repairs.

Qatar is a major supplier of LNG to European and Asian markets.-Reuters