Last year has proved to be one of the best years for schedule reliability among container shipping lines, especially the second half of 2015 when "global schedule reliability reached considerably higher performances from September to December compared to previous years," said SeaIntel CEO Alan Murphy.

Furthermore, last year saw the difference between the best and worst ocean liners in the top 20 narrowing, a SeaIntel study concluded.

Backing up the findings of Drewry last month, SeaIntel said liner on-time performance rose by 13.3 percentage points in December compared to the same month the previous year, to reach a global score of 84.6 percent, reported Lloyd's Loading List.

"Towards the second half of 2015 global on-time performance returned to 2012/2013 levels, while we have increasingly seen less diversity in performance across carriers, as alliances in the east/west trades and vessel sharing agreements and slot charters in the north/south trades led to less differentiation," said Mr Murphy.

SeaIntel said that Wan Hai retained its top position in its December Global Top 20 carrier rankings with 91 percent on-time performance, followed by MOL at 90.1 percent, Maersk at 89 percent and Hamburg Sud at 87.7 percent.

At the other end of the scale, CMA CGM was 84.1 percent on time, Zim 84.2 percent and NYK 85.2 percent.

"For yet another consecutive month since August 2015, the difference between number 1 and 20 has remained under 10 percentage points, decreasing from 9.1 percentage points in November to the lowest level ever recorded of 6.9 percentage points in December," said the report.