Shadow Welsh Secretary Peter Hain has called for better resources for mine rescue services after claiming the Swansea Valley Gleision disaster highlighted "potentially lethal" flaws.
The Neath MP claimed there were disputes over bills, and some rescue costs were met by a nearby mining company.
David Powell, 50, Charles Breslin, 62, Philip Hill, 44, and Garry Jenkins, 39, died after the mine was flooded.
The four men died, and three others escaped, when the Gleision drift mine, near Pontardawe, flooded last month.
In a report sent to Home Secretary Theresa May, Mr Hain wrote: "The Gleision mine tragedy identified a potentially lethal flaw in the resourcing of the Mines Rescue Service and the South Wales Police Authority, which the (UK) Government needs urgently to address.
"Otherwise, should there be another tragedy, both the rescue and investigation could be badly compromised: only goodwill prevented that happening at Gleision.
"At a number of stages, in first the rescue attempt and second the investigation, there were disputes about paying bills and the nearby Walters Mining at Aberpergwm did in fact pay a £4,500 bill for diesel fuel for generators to drive the water pumps.
"Had Walters not stepped in and volunteered to do so (without any certainty of getting their money back) the rescue attempt could have been seriously jeopardised."
Mr Hain also claimed the rescuers, and later police and health and safety inspectors, "depended upon the release by other mining companies of their part-time mines rescue staff as well as other key mining personnel".
He said: "In most mines rescue situations, the 'first response' is made up of a combination of permanent corps staff and mine-based part-time rescue workers. This was also the case at Gleision and became even more difficult to manage as the rescue activities passed into the investigation phase when the mines inspector had to phone Walters Mining, Unity Mining and Metal Innovations Ltd to request they release their miners and craftsmen to provide extra rescue assistance."
He described such companies as "unsung heroes", adding: "To their credit there was never any question of the companies not co-operating.
"But they were not paid for the release of men, who would otherwise have been working productively underground for companies which have to survive in a tough, competitive marketplace."
His report to the Home Secretary he also said it was "intolerable" that South Wales Police should be landed with a bill of more than £200,000 when their budget had been cut by £19 million.
He also urged Work and Pensions Secretary Iain Duncan Smith, to "resource the Mines Rescue Service properly".
He added: "The principal mines inspector together with rescue and other workers performed heroically throughout the three weeks of the operation.
"But that should not detract from the very serious flaws Gleision has revealed.
"These must be urgently addressed by the Government."