Last week saw three to four charters that added significant pressure on rates, although no deals were reported to have exceeded the $33,000 mark.
One source said that some Atlantic shipowners had shied away from raising rates due to fears it would sabotage chartering activity just as it was picking up.
However, the sheer number of charters and growing vessel requirements from LNG producing countries has made further chartering virtually impossible, the source said.
"Unless you have a shipping position, it will be almost impossible to get a ship in the next six to eight weeks, and if any charters are extended then it will be longer," they said.
Nigeria, which has filled one requirement already, is looking for "at least" a further five vessels after ramping up production from its Bonny Island liquefaction plant.
Qatari producer RasGas is rumoured to be looking to re-enter the market for further ships, another source said.
Northwest Europe has become the launching pad for diversions into Asia, with sellers netting premiums of around $2.5/MMBtu by sending cargoes into pricier Far Eastern markets.
The longer return journey times associated with sailing Atlantic ships into the Pacific basin is another constricting factors on availability, shipping brokers said.