By Jessica Jaganathan and Emily Chow

Global gas prices hit multi-year highs this week as rising temperatures are driving up demand for power generation during the northern hemisphere summer and as traders in some regions replenish stocks ahead of winter.

Prices for liquefied natural gas (LNG) cargoes delivered in Asia rose above $13 per million British thermal units (mmBtu) this week, highest for this time of the year since 2013, while British wholesale and U.S. natural gas prices also rose to multi-year highs.

"Post-lockdown demand recovery, together with a wide collection of exogenous hits to supply/trade flows worldwide, have lifted gas prices (year-to-date) in all key markets," analysts from investment bank Liberum said in a note this week.

June shipments to Japan climbed 18% from the previous month to a three-month high of 6.01 million tonnes, Refinitiv Eikon shiptracking data showed, as utilities are ensuring adequate power supply in anticipation of a hot summer and ahead of the Tokyo 2020 Olympic Games due to start on July 23.

China imported about 6.4 million tonnes of LNG in June, a drop from May but still about 26% higher than the same period last year, the data showed.

"We are seeing a lot of buying now (in China) in preparation for winter after last year," a Singapore-based LNG trader said, adding that buyers are undeterred by high spot prices even though it means a loss for them, with Chinese domestic wholesale prices currently lower than spot LNG prices.

A China-based trader said robust buying from China is also being spurred by energy security reasons as they want to avoid a situation like last winter when spot prices rose to above $30 per mmBtu amid gas shortages.

The two traders declined to be named because they are not authorised to speak with media.

Buyers in Bangladesh and Pakistan have also paid above $13 per mmBtu for cargoes to be delivered in July to meet summer air-conditioning demand, sources said.

Global gas supply was curtailed this year as Russian gas supply to Europe was cut 15%-20% compared with 2019 levels exacerbating an already low-inventory level situation in Europe, Liberum analysts said.

Reflecting the drop, Russia's Gazprom did not book any interruptible transit capacity through Ukraine for July despite planned maintenance on alternative routes.

British and Dutch front-month gas prices rose to 13-year highs on Thursday, amid lower flows from Norway, wider supply concerns and as storage levels remain very low.

U.S. natural gas futures hit 30-month highs this week on forecasts for higher-than-expected U.S. air-conditioning and export demand over the next two weeks.