UK oil rigs are becoming safer but improvements must continue, according to a report published on Tuesday.

The offshore industry was praised by the Health and Safety Executive (HSE) for its "serious commitment" to safety after a number of concerns were addressed. However, following its review the HSE also warned that the current economic climate must not act as a barrier to progress.

The HSE findings were based on a review of progress since a major safety report was published in November 2007. The report was based on a three-year investigation into safety on more than 100 offshore installations. It was prompted by safety failures on installations and the deaths of two workers in 2002.

Among the improvements found by the review was work done to address areas of serious concern, including fire doors and deluge systems.

There was also said to be "significant resources" being devoted to hazard awareness, and better sharing of information between organisations. General maintenance on installations was also said to be improving, although the review noted that ageing infrastructure made this an "ongoing challenge".

Judith Hackitt, HSE chairman, said: "There are a number of positives to draw from this review, most notably that work has been undertaken to deal with all the issues that posed the most serious concern.

"We do recognise the serious commitment the industry in making the improvements and the considerable resources that are required."

But she warned the economic slowdown must not halt progress, adding: "Learning from past mistakes means not squeezing key resources at the very time ageing installations and infrastructure need investment."

Malcolm Webb, chief executive of leading industry body Oil and Gas UK, said: "This thorough HSE review very clearly shows the immense progress the industry has made. Union leaders say the report, while welcome, is only a snapshot of the industry.

"Importantly, the report states it is essential that fluctuating economic environments should not slow up progress on management approaches to achieve and sustain improvements," said Jake Molloy, RMT Regional Organiser.

"It is difficult to see how these improvements can be sustained in cases such as BP announcing significant cuts to workers terms and conditions, and Shell announcing a 20% cut to engineering and maintenance support staff onshore."

Despite the praise, Union leaders insist there is still much to do.

Jake Molloy of the RMT Union said: “In the last four weeks we’ve come very close to killing four people – not directly related to the KP3 aspect of things but it just proves that we need to maintain vigilance”.