The Piper Alpha disaster in 1988 claimed 167 lives
The safety of the UK's offshore installations is improving but the "challenges are ongoing", the Health and Safety Executive has said.
The HSE review said work had taken place to rectify issues giving concern.
Judith Hackitt, from HSE, said: "This is a work in progress and the momentum for improvement must continue."
Malcolm Webb, chief executive of industry body Oil and Gas UK, said: "This review clearly shows the immense progress the industry has made."
The review comes 18 months after a critical report that followed a major three-year investigation into safety on more than 100 offshore installations.
There was one major gas leak last year in the North Sea on a scale comparable to the one that caused the explosion on Piper Alpha 21 years ago. Two years ago there were five.
Ian Whewell, head of HSE's offshore division, said: "Though the findings of this review are encouraging, the challenges are ongoing and should not be underestimated.
"The offshore infrastructure continues to get older and remedial work in some areas is yet to be completed. Momentum must continue to prevent the assets degrading to the unacceptable levels identified in the 2007 KP3 report.
Jake Molloy called for greater workforce involvement
"Though we appreciate that fluctuating demand cycles provide further challenges to the industry in planning and allocating resources, this will not be permitted as an excuse for poor asset integrity."
He added: "The benefits of good safety are unchanged even in the current downturn."
Oil and Gas UK's Mr Webb added: "We are pleased that all the matters that gave rise to significant concern, the so called 'red light issues', have been resolved satisfactorily.
"This industry will continue to invest directly in safety, asset integrity, skills and training throughout the economic cycle to ensure that safety continues to be our top priority. We can do no less."
Jake Molloy, of the OILC/RMT union, said: "We feel the most important area to bring about the desired improvements lies in greater workforce involvement.
"The report rightly refers to 'the dynamic nature of safety systems' and the 'need to monitor them continuously'.
"In our opinion there is no other group better positioned to fulfil this role than the people exposed to the greatest risks - the workforce."