Just months before the first stage of Canberra's light rail was due to open, the Government was delivered a grim conclusion by the electrical certifier: "most of the Canberra Metro site" was non-compliant.

Key points: Documents released under FOI laws allege unlicensed workers installed electrical works

Documents released under FOI laws allege unlicensed workers installed electrical works Cables were laid too close to the surface, concrete was cracked, pits were flooded

Cables were laid too close to the surface, concrete was cracked, pits were flooded Despite this, Canberra Metro Construction pushed forward with intended start date

Despite this, Canberra Metro Construction pushed forward with intended start date The Government says the light rail system is both popular and safe

At its lowest ebb, the light rail track was riddled with failures: flooded electrical pits, broken conduits, high voltage cables accessible by the public and cracking concrete slabs.

One of the biggest issues was the protective electrical conduit running alongside the track, allegedly installed, at least in part, by unlicensed workers. The entire length of it had to be rectified due to holes, deformities, leaks and rubble, compromising its integrity from end to end.

When the electrical certifier refused to sign off on these issues, the Canberra Metro Construction (CMC) consortium found a new one.

These problems were revealed in documents released under freedom of information (FOI) laws.

Communications between ACT Government staff, certifiers and the CMC consortium within those documents suggest a pattern of company management eager to push ahead when faults were identified, sometimes requesting the problems be left "as is".

According to the documents, even as the CMC consortium's own workers wrote to the certifier about emerging issues — describing them as "what f**ked looks like" — they continued to plan for a December launch.

In those documents, the CMC consortium pointed the finger at an inflexible Government putting them under unreasonable time constraints.

Allegations CMC were 'reckless' about licenses, piping

Piping and damaged electrical conduits were littered throughout the construction of stage one of Canberra's light rail network. ( Supplied )

In June of last year, the CMC consortium was preparing to sign off on the light rail's electrical works — months earlier it had already begun testing along the northern end of the track.

It sent off documentation to get the all-clear from the electrical certifier, Specialist Electrical Engineering Group (SEEG) director Tony Berryman.

Four months later, Mr Berryman returned with alarming findings.

He alleged that the CMC consortium had committed offences using unlicensed workers and supervisors to install electrical works, and installed high-voltage joints inside pits flooded with water.

"CMC has been reckless about whether workers installing electrical conduit[s] have electrical licences," one SEEG official wrote.

Mr Berryman found hundreds of metres of conduit piping was compromised, cables were laid too close to the surface, concrete was cracking and at least 60 pit connections with high voltage cables were potentially compromised by water.

The Government's technical regulator was brought in after SEEG complained that the CMC consortium was not cooperating with them. Senior manager of the regulator, Simon Grice, was warned that the leaky pits could cause an explosion.

"Connections were not waterproof and pits [were] subject to flooding, which could result in explosion in the public domain," Mr Grice wrote in an email to colleagues.

When the protective piping encasing the light rail's wiring was inspected by remote cameras, it turned up metres upon metres of problems.

In one 80-metre stretch of piping, the inspection found cracks, peeled-back joints, water leaks, bulging and rubble.

Flooded electrical pits during construction of Canberra's light rail stage one were at risk of causing an explosion. ( Supplied )

CMC push forward despite issues

But at the same time as these technical issues were emerging, the CMC consortium was pushing forward with its intended December 21st start date, suggesting some problems could be left "as is" or solved with a "temporary" fix.

It continued rail testing and driver training, working around sections where the certifier had shut down parts of the track because water was getting into the electrical pits.

SEEG's Mr Berryman refused to certify the electrical works as they were; the CMC consortium ultimately sought out a new certifier in December.

As the CMC consortium's deadline for light rail loomed, the frustration from government staff over their attitude to the problems grew.

In an email following a meeting with the CMC consortium at the end of October, Transport Canberra's technical lead Peter Stanford wrote that "CMC management just want a quick fix".

He wrote that it was a "disappointing" meeting, where the consortium sought to "rubber stamp" the non-compliant issues.

"[The certifier] reiterated that no matter what ideas CMC may have, the construction is not to Australian Standards and the Electrical code."

Mr Stanford said in one instance workers were told to stop pouring concrete over cabling that had been found to be non-compliant, but continued anyway.

"You will find [the certifier], [redacted] and [redacted] even told them to stop, but they didn't as they had been 'told by others' to go! … CMC are not responding to issues raised," he wrote.

In another email between government staff, the electrical lead for the government's technical regulator, Gordon Kelly, wrote that from the information he had, "most, if not all installation (sic) fail".

He later wrote he was no longer accepting any verbal advice or determinations from the CMC consortium, "As it is just not working out there on site."

Cracked concrete and pooling, seen during construction of stage one of Canberra's light rail network. ( Supplied )

"My experience, along with those senior engineers of [the Australian Corrosion Association] continue (sic) to witness poor industry practices," Mr Kelly wrote.

Mr Grice wrote that the CMC consortium were trying to get around the issues being raised.

"I recommend that we don't attend a meeting with [Canberra Metro Operations] without taking technical officers to the meeting because CMC/John Holland will seek to engage us in a technical argument if we don't agree with or criticise their proposed approach," Mr Grice wrote in one email.

CMC cites government pressure

In the released documents, the CMC consortium contended that some of the poor installations were because the Government was pressuring them to meet an unreasonable deadline.

In one technical paper, a CMC consortium official wrote:

"A number of issues prevented the original design being adhered to, the main one being the time available for the work to occur … The time requested was not granted/available."

CMC were working to a contract which stipulated it would forfeit payment for every month the consortium ran over an agreed September 1 deadline.

It ended up losing $22 million because of that stipulation.

The ACT Government also ultimately paid CMC $76.1 million in contingency to settle construction claims, roughly $30 million less than it had anticipated paying.

Government 'confident in the safety of the project'

Canberra light rail is now up and running and the Government says it is confident all safety issues have been resolved. ( ABC News: Jake Evans )

The technical regulator's delegate, Dave Peffer, said he was confident any electrical issues had been resolved.

"The operating certificate would not have been issued if we weren't confident in the safety of the project," Mr Peffer said.

"The fact issues were identified and ultimately rectified by Canberra Metro isn't a problem — it's a sign of regulation in action.

"It shows the protections in place worked to support the delivery of a safe project."

In a statement on behalf of the CMC consortium, a government spokesman wrote that there were no concerns with the light rail system.

"It's not only an extremely popular light rail system, but one that is safe and which will service Canberra for many decades to come," the statement read.

"Canberra Metro undertook rectification works where necessary and undertook a level of verification activities that went beyond what is typical for similar projects.

"The ACT Government is exceptionally pleased with the light rail system that has been delivered for Canberrans."

Opposition calls for independent safety assessment

Mr Peffer said while some piping had to be replaced, he was confident in the new certifier's decision to sign off on rectification work or decisions to leave "as is".

He said the CMC consortium was able to resolve some shallow cabling by adding an extra layer of concrete or installing marker plates to warn future workers of buried cables.

The CMC consortium was also able to install an additional pit that drained the groundwater from flooded electrical pits and relieve the pressure that was leading to leakage.

Neither the ACT Government or the CMC consortium were able to answer the ABC's questions as to what the new certifier approved "as is".

Spokeswoman for the ACT Opposition Candice Burch said the light rail needed an urgent and independent safety assessment.

"The Government is telling Canberrans to trust that they've fixed the problem without providing any detail on how the situation has been remedied," Ms Burch said.

The CMC consortium is expected to be given the contract to plan, design and deliver the expansion of the light rail through to Woden.