Shallower Panama Canal draughts may help firm freight rates and provide the basis for further ­ increases by limiting the amount of cargo that some lines can carry from Asia to the US East Coast.

But the tightness in the market could be under­mined by lines adding capacity to the trade in an ­effort to cash in on the firming market.

Spot rates from Asia to the US have held steady in recent weeks. Rates to the US East Coast for the week ending 12 July rose slightly to $2,962 per 40-foot equivalent unit (feu), while rates from Asia to the US West Coast held steady at $1,646 per feu, according to the Freightos Baltic Index.