The number of vessels that failed to comply with Maritime Labour Convention (MLC) standards has increased by 4% to 2,755 last year, according to the International Transport Workers’ Federation (ITF).

Conducted between 20 August 2014 and 19 August 2015, the survey considered the real-time experiences of seafarers, and covers problems found on vessels flying all flags.

Panama reported the highest number of problems, while St Kitts and Nevis had the highest percentage of problematic inspections.

"An optimistic explanation for the increase might be that the convention provides mechanisms that make it easier for seafarers to make complaints."

Frequently reported problems were primarily related to unpaid wages and payment of wages below International Labour Organisation (ILO) minima. Since MLC came into force in 2013, ITF inspectors have recovered around $89m.

ITF maritime coordinator Jacqueline Smith said: "The ITF had expected that the increase in flag states to which the convention applies would have resulted in an improvement in the standards of living and working conditions for seafarers on board their vessels, but based on the number of problems received, this unfortunately does not seem to be the case.

"An optimistic explanation for the increase might be that the convention provides mechanisms that make it easier for seafarers to make complaints.

"If this is the case, then we can only speculate how many problems went unaddressed prior to the entry into force."

In 2013, the convention was in force in 30 countries. Currently, 60 of the 65 countries that have now ratified are acceded to the MLC regime.