LONDON (Reuters) - Egypt is seeking large volumes of gas from global markets this summer with deferred payments of up to six months, terms that market sources said would narrow the list of bidders and increase premiums at a time of high competing demand from Asia.

The most populous Arab country had been setting itself up as a reliable LNG exporter to Europe in recent years, but dwindling natural gas supplies have forced Cairo to return to being a net importer of gas.

In a tender that closes on June 26, Egypt's Natural Gas Holding Company (EGAS) is seeking delivery of 17 LNG cargoes, seven in July, six in August and four in September on an ex-ship (DES) basis, trading sources told Reuters.

To secure the requested volumes, Egypt could eventually pay more than the average premium of between $1 and $2 per million British thermal unit (mmBtu) to the Dutch TTF hub gas price, the sources said.

"Any longer-term payment terms would warrant an additional premium," one source said.

Cairo has already paid a premium to the TTF price of between $1.30 and $1.70 per mmBtu for cargoes it bought earlier this year, S&P data showed.

Egypt's petroleum ministry did not respond immediately to a request for comment during the Eid holiday.

There is robust Asian demand for Atlantic volumes, which are also expected to be the main source of Egypt's supply, as the Bab al-Mandab strait remains effectively closed because of Middle East tensions.

"It is likely only Atlantic LNG supply would be competitive in this tender. But demand from Asia, particularly Japan, has been stronger in recent weeks than had been anticipated by many," said Samuel Good, head of LNG pricing at commodity pricing agency Argus.

"Any non-standard elements in the tender terms would further buoy this premium."

The Hoegh Galleon floating storage and regasification unit (FSRU), which arrived at Ain Sokhna port last week, is expected to handle 12 of the expected cargoes while five others will be received at the Aqaba port in Jordan, the sources said.

Several traders said they are giving the tender careful consideration. The tender is for Egypt's largest purchase in years and comes against a backdrop of concern over the country's credit risk and difficult economic situation.

Egypt's economic challenges and shortage of foreign currency has left the government with billions of dollars in receivables owed to major oil and gas companies, two other sources at major oil and gas companies told Reuters.

The government has recently resumed payments to some producers.

(Reporting by Marwa Rashad and Ron Bousso in London; Additional reporting by Julia Payne in Brussels; Editing by Kirsten Donovan and David Goodman)

By Marwa Rashad and Ron Bousso